fix orientation in image-backend, not in preview system itself
Tentative fix for legacy file actions unit test side effect

Sometimes the JS unit test with legacy file actions fail.

This fix runs the legacy file actions tests on a dummy instead of the
real one.
Check if the parent is writable to check if a file is deletable
Check if a folder is deletable before we try to recursively delete it
Also check if the file itself is updatable
Fix mapping of relative paths
Merge pull request #10622 from owncloud/recursive-delete-forbidden

Fix isDeletable
Merge pull request #9554 from owncloud/fix_preview_orientation

fix orientation in image-backend, not in preview system itself
Merge pull request #11105 from owncloud/jsunit-legacyfileactionsfix

Tentative fix for legacy file actions unit test side effect
Resolves cache tests failing if the directory length is longer than 64