winbind: Allow winbindd to be run from inside "samba"

Change-Id: I6b90a9b62ba5821e0feedb23cd20642078ba0ca6
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Kamen Mazdrashki <kamenim@samba.org>

Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Tue Apr 29 05:28:39 CEST 2014 on sn-devel-104