it is not possible to unshare files in OC5
Merge pull request #6207 from owncloud/stable5_unshare_vs_delete

Stable5 unshare vs delete
reuse etags when doing a background scan
extend test case for etag preservation
get rid of failing test that don't cause additional downloads
don't check migration status if a file is accessed by a public link
Merge pull request #6232 from owncloud/stable5-backgroundscan-reuse-etag

Stable5 backgroundscan reuse etag
Merge pull request #6258 from owncloud/stable5_enc_fix_public_access

don't check migration status if a file is accessed by a public link