Make it possible for storage implementations to disable part files

[PVince81]

A storage implementation must be able to decide whether parts files are needed or not needsPartFile.

Some storages like GDrive and Dropbox do not really need it because uploading a file there doesn't result in partial file content. The atomicity is guaranteed by the provider.
Unlike SMB or FTP.

See https://central.owncloud.org/t/issue-with-versioning-on-google-drive/1683/9 for context

[PVince81]

1. Add a new optional interface method needsPartFile that returns true by default in the \OC\Files\Storage\Common class
2. Add check that calls this method here https://github.com/owncloud/core/blob/v9.1.4/apps/dav/lib/Connector/Sabre/File.php#L508

[PVince81]

3. Make the classes in question return false when needsPartFile is called.
4. Make the GDrive and Dropbox storage classes return false too

[ownclouders]

Hey, this issue has been closed because the label status/STALE is set and there were no updates for 7 days. Feel free to reopen this issue if you deem it appropriate.

(This is an automated comment from GitMate.io.