smbd: use owner uid for free disk calculation if owner is inherited

smbd: use owner uid for free disk calculation if owner is inherited

If "inherit owner" is enabled, then new files created under a
directory shall consume the quota of the directory's owner, so
the free disk calculation should take that quota into account,
not the quota of the user creating the file.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12145

Signed-off-by: Uri Simchoni <uri@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
(backported from commit ea73bcd87b6113f77ccda683d15b5a39003b8eaa)