smbd - allow updates on directory write times on open handles.
If we set a non-null 'old timestamp' in the share mode database
when creating a directory handle, this prevents mtime (write time)
updates from being seen by clients, as we will always return the
timestamp stored in the database whilst the handle is open.
For files this is ok, as we update the stored timestamp
ourselves when we write to the handle. For directories
we should just rely on the mtime value from the underlying
filesystem.
Torture test to follow.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=9870
Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>