[QA] files_external_dropbox never checks for changes

[jnweiger]

Seen with files_external_dropbox 2.0.0-rc.1 on core 10.11.0-alpha.2

• Upload a text file thing.txt into your dropbox account.
• Create an app 'jw-qa' at http://www.dropbox.com/developers with access to the entire account.
• Copy paste the key and secret from there,
• Paste the https://OWNCLOUD_SERVER_NAME/index.php/settings/admin?sectionid=storage url into Redirect URI
• Connect a 'Dropbox V2' external storage with key and secret. After an oauth roundrip, the storage is green. OK.

• confirm that the option check for changes: once every direct access is set.

• Check the contents in the owncloud external storage. thing.txt is there.
• At the dropbox server rename thing.txt to renamed_thing.txt
• Check the contents in the owncloud external storage. It still shows thing.txt. BAD
• Try access thing.txt -> internal server error. BAD

Expected behaviour:

• the setting check for changes: once every direct access differs from the setting check for changes: never

Workaround:

• occ file:scan --all
• Now the file renamed_thing.txt appears (and can be edited, if the patch from https://github.com/owncloud/files_external_dropbox/issues/138#issuecomment-1200547747 is installed)