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

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.