fix, pass on UO_ANON flags to ute_sort()

UO_ANON opened files will stay UO_ANON (unlinked in the filesystem) when
sorting takes place.

This should fix an issue with the new test suite where no test left-overs
are really welcome.

Signed-off-by: Sebastian Freundt <hroptatyr@fresse.org>
Merge branch 'core/file' into next

* core/file:
  fix, pass on UO_ANON flags to ute_sort()