lib: Fix server_id_db_set_exclusive

lib: Fix server_id_db_set_exclusive

For server_id_db_set_exclusive we need to store the unique id along
with the vnn:pid combo. I had tested all this just with some
smbtorture and net command tests, all of which have a unique id of
zero. When trying to exclusively register "notify-daemon" when smbd
is running, this fails because serverid_exists only tests with zero
unique id. notifyd does have a non-zero unique id, so server_id_exists
will think the existing notifyd is another non-samba process that
happened to claim notifyd's pid.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Thu Oct  1 02:53:58 CEST 2015 on sn-devel-104