Fix the error that generates wrong path separators

[kmorihiro]

When current directory is root directory (e.g. / or C:/), vaffle#env#create_items() generates wrong duplicated path separators (e.g. //bin or C://Windows).

[cocopon]

Thank you for the pull request! But I cannot reproduce the behavior... Would you share your environment (OS, Vim version, etc.) and .vimrc?

[kmorihiro]

Thank you for your review and sorry for late reply.

I confirmed it under the following environment.

Case 1:

• OS: Windows 10 / 7 Pro
• Vim version: Vim 8.0.596 64bit Kaoriya version (compiled at 2017-05-02)
• minimum .vimrc: no .vimrc (use $VIM\vimrc only.) git-clone vaffle.vim to %USERPROFILE%\vimfiles\pack\my\start\vaffle.vim\
• step to reproduce:
  1. open vim.exe and type :cd C:\
  2. type :Vaffle. Now, a statusline shows vaffle://0/C:\.
  3. open one of folders (e.g. Users/) and type h to back to C:\. Now, a statusline shows vaffle://1/C:\\.
  4. repeat step (iii) several times. A statusline shows vaffle://0/C:\\/////Users.

Case 2:

• OS: Cygwin 64bit 2.6.1-1 on Windows 10
• Vim version: Vim 8.0.244 (compiled at 2017-01-27)
• minimum .vimrc: no .vimrc (use /etc/vimrc only.) git-clone vaffle.vim to ~/.vim/pack/my/start/vaffle.vim/
• step to reproduce:
  1. open vim and type :cd /
  2. type :Vaffle. A console shows (no items).

[cocopon]

Really sorry for the late response... :bow: I can reproduce the bug, thank you for the detailed description!