Delete Attachment Missing In 1.14

[kdumontnu]

• Gitea version (or commit ref): 1.14.1+18-g3bde29712
• Operating system: Windows, Firefox (running locally)
• Database (use [x]):
  • [X] PostgreSQL
  • [ ] MySQL
  • [ ] MSSQL
  • [ ] SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • [ ] Yes
  • [X] No (seems to work in 1.15)
• Log gist (nothing useful):

  
  2021/04/29 09:58:50 Completed GET /user/events 200 OK in 1m57.7774715s
  2021/04/29 09:58:50 Started GET /test/testRepo/releases/edit/tester for 127.0.0.1:54264
  [git-module] C:\Users\Kyle\Documents\5 - Software Development\gitea\data\gitea-repositories\test\testrepo.git: C:\Program Files\Git\mingw64\bin\git.exe -c credential.helper= -c protocol.version=2 -c filter.lfs.required= -c filter.lfs.smudge= -c filter.lfs.clean= show-ref --tags
  [git-module] C:\Users\Kyle\Documents\5 - Software Development\gitea\data\gitea-repositories\test\testrepo.git: C:\Program Files\Git\mingw64\bin\git.exe -c credential.helper= -c protocol.version=2 -c filter.lfs.required= -c filter.lfs.smudge= -c filter.lfs.clean= show-ref --heads
  [git-module] C:\Users\Kyle\Documents\5 - Software Development\gitea\data\gitea-repositories\test\testrepo.git: C:\Program Files\Git\mingw64\bin\git.exe -c credential.helper= -c protocol.version=2 -c filter.lfs.required= -c filter.lfs.smudge= -c filter.lfs.clean= show-ref --verify -- refs/heads/master
  [git-module] stdout:
  7b24e68d4b327acf4fba1ad7e55b108c7391f697 refs/heads/master

[git-module] C:\Users\Kyle\Documents\5 - Software Development\gitea\data\gitea-repositories\test\testrepo.git: C:\Program Files\Git\mingw64\bin\git.exe -c credential.helper= -c protocol.version=2 -c filter.lfs.required= -c filter.lfs.smudge= -c filter.lfs.clean= show-ref --verify --hash refs/heads/master [git-module] stdout: 7b24e68d4b327acf4fba1ad7e55b108c7391f697

[git-module] C:\Users\Kyle\Documents\5 - Software Development\gitea\data\gitea-repositories\test\testrepo.git: C:\Program Files\Git\mingw64\bin\git.exe -c credential.helper= -c protocol.version=2 -c filter.lfs.required= -c filter.lfs.smudge= -c filter.lfs.clean= cat-file --batch 2021/04/29 09:58:50 Completed GET /test/testRepo/releases/edit/tester 200 OK in 393.3139ms 2021/04/29 09:58:50 Started GET /css/easymde.css?v=a392a7ce355662caa780d91e9f81b56f for 127.0.0.1:54264 2021/04/29 09:58:50 Completed GET /css/easymde.css?v=a392a7ce355662caa780d91e9f81b56f 200 OK in 1.9174ms 2021/04/29 09:58:50 Started GET /vendor/plugins/codemirror/addon/mode/loadmode.js for 127.0.0.1:54264 2021/04/29 09:58:50 Started GET /css/index.css?v=a392a7ce355662caa780d91e9f81b56f for 127.0.0.1:54266 2021/04/29 09:58:50 Started GET /js/easymde.js?v=a392a7ce355662caa780d91e9f81b56f for 127.0.0.1:54267 2021/04/29 09:58:50 Started GET /vendor/plugins/codemirror/mode/meta.js for 127.0.0.1:54268 2021/04/29 09:58:50 Completed GET /js/easymde.js?v=a392a7ce355662caa780d91e9f81b56f 200 OK in 9.7218ms 2021/04/29 09:58:50 Started GET /js/index.js?v=a392a7ce355662caa780d91e9f81b56f for 127.0.0.1:54267 2021/04/29 09:58:50 Completed GET /css/index.css?v=a392a7ce355662caa780d91e9f81b56f 200 OK in 10.8201ms 2021/04/29 09:58:50 Completed GET /vendor/plugins/codemirror/mode/meta.js 200 OK in 11.3551ms 2021/04/29 09:58:50 Completed GET /vendor/plugins/codemirror/addon/mode/loadmode.js 200 OK in 18.9973ms 2021/04/29 09:58:50 Completed GET /js/index.js?v=a392a7ce355662caa780d91e9f81b56f 200 OK in 10.7836ms 2021/04/29 09:58:51 Started GET /img/logo.svg for 127.0.0.1:54266 2021/04/29 09:58:51 Started GET /avatar/11028eaca8875278ff303fd1d3fa710e?size=48 for 127.0.0.1:54268 2021/04/29 09:58:51 Completed GET /img/logo.svg 200 OK in 4.1622ms 2021/04/29 09:58:51 Completed GET /avatar/11028eaca8875278ff303fd1d3fa710e?size=48 302 Found in 5.4799ms 2021/04/29 09:58:51 Started GET /img/logo.svg for 127.0.0.1:54267 2021/04/29 09:58:51 Completed GET /img/logo.svg 200 OK in 2.8746ms 2021/04/29 09:58:52 Started GET /css/dropzone.css for 127.0.0.1:54267 2021/04/29 09:58:52 Started GET /js/dropzone.js for 127.0.0.1:54266 2021/04/29 09:58:52 Completed GET /css/dropzone.css 200 OK in 6.5215ms 2021/04/29 09:58:52 Completed GET /js/dropzone.js 200 OK in 6.2262ms 2021/04/29 09:58:52 Started GET /js/tribute.js for 127.0.0.1:54267 2021/04/29 09:58:52 Completed GET /js/tribute.js 200 OK in 2.0021ms 2021/04/29 09:58:52 Started GET /js/index.js.map for 127.0.0.1:54271 2021/04/29 09:58:52 Started GET /fonts/fontawesome-webfont.woff2 for 127.0.0.1:54267 2021/04/29 09:58:52 Completed GET /fonts/fontawesome-webfont.woff2 200 OK in 1.5208ms 2021/04/29 09:58:52 Completed GET /js/index.js.map 200 OK in 25.7884ms 2021/04/29 09:58:52 Started GET /js/eventsource.sharedworker.js for 127.0.0.1:54267 2021/04/29 09:58:52 Completed GET /js/eventsource.sharedworker.js 200 OK in 3.7662ms 2021/04/29 09:58:52 Started GET /fonts/fontawesome-webfont.woff2 for 127.0.0.1:54267 2021/04/29 09:58:52 Completed GET /fonts/fontawesome-webfont.woff2 200 OK in 3.9196ms 2021/04/29 09:58:53 Started GET /css/index.css.map for 127.0.0.1:54271 2021/04/29 09:58:53 Completed GET /css/index.css.map 200 OK in 5.2663ms 2021/04/29 09:58:53 Started GET /user/events for 127.0.0.1:54267

## Description
Delete attachments (https://github.com/go-gitea/gitea/pull/14130) seems to not work in version `1.14` without error. 

To reproduce - create a new release, upload an attachment, select "edit" and you should not see the list of attachments.

It DOES appear to work on master (even when I tested locally on Windows).

## Screenshots
![image](https://user-images.githubusercontent.com/12700993/116581072-340f9600-a8d1-11eb-985d-044922fe3e92.png)

![image](https://user-images.githubusercontent.com/12700993/116581111-3d006780-a8d1-11eb-88d8-ce4300ee86e5.png)

[kdumontnu]

@lunny FYI

[fnetX]

Simply not in 1.14, right? Milestone is 1.15 and I don't see any backport, so this is probably to be expected (no bug, but a still missing feature)

[kdumontnu]

Simply not in 1.14, right? Milestone is 1.15 and I don't see any backport, so this is probably to be expected (no bug, but a still missing feature)

Good point - I got mixed up there (thought this made it into 1.14). Will discuss whether a backport makes sense.

[6543]

Ref: https://github.com/go-gitea/gitea/pull/15666