Fix bug #6297 - owner of sticky directory cannot delete files created by

Fix bug #6297 - owner of sticky directory cannot delete files created by
others.
The reason we couldn't delete was we were erroring out early
if requestor was not the owner of the file we wanted to delete,
instead of checking if the requestor owned the directory as well.
If either of these is true, we must go on and check the ACL.
Karolin, this is a must for 3.4.0 and also 3.3.next. I'll update
the bug report with patches for 3.4.0 and 3.3.next and ask vl
to review.
Jeremy.
(cherry picked from commit cea3a63a86a733a16c3e91f5a78e972be802eb5c)