Fix timestamp and rollback of versions

[XueSheng-GIT]

Fix #2055 and fix #2077

File versioning for groupfolders is still broken. I'm not a programmer but after some investigation this change does improve things. This is my first pull request, thus I'm not sure whether this is the right way to go. Feel free to guide me into the right direction! Thanks.

[XueSheng-GIT]

@juliushaertl @ArtificialOwl Any hints how to proceed with this? This is my first pull and I'm a bit lost what else I have to do. Thanks for your support.

[XueSheng-GIT]

@solracsf thanks for your hints! Commits should have been squashed now and DCO seems to be successful now.
Anything else I can do to get this merged?

[solracsf]

Marked for review, wait for CI to complete, fix any errors (if any) and wait for it to be reviewd and merged :)

[XueSheng-GIT]

Coding standards check failed because $version->getRevisionId() is no int? But actually it is!?

[solracsf]

What about:

$targetMount->getStorage()->touch($targetInternalPath, intval($version->getRevisionId()));

By wrapping $version->getRevisionId() with intval(), you ensure that the second argument passed to touch() is an integer. This should resolve the InvalidScalarArgument error.

[XueSheng-GIT]

Closing this pull in favour of #2543