s3:smb2_find: Return that timestamps do not exist as directories

s3:smb2_find: Return that timestamps do not exist as directories

When a Windows client receives a large directory listing while
querying snapshots, it sends a find request asking for the
timestamp as a directory. A Windows server returns NO_SUCH_FILE,
so make sure Samba returns the same. Otherwise the client will
get confused and display timestamps in the 'previous versions' dialog.

Signed-off-by: Christof Schmitt <christof.schmitt@us.ibm.com>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Tue Sep 10 22:38:51 CEST 2013 on sn-devel-104