messaging: Always register the unique id

messaging: Always register the unique id

The winbind child does not call serverid_register, so the unique id is not
registered. ctdbd_process_exists now calls CTDB_CONTROL_CHECK_PID_SRVID, which
then fails.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=13180
Signed-off-by: Volker Lendecke <vl@samba.org>
Autobuild-User(v4-7-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-7-test): Fri Dec 15 15:35:25 CET 2017 on sn-devel-144

(cherry picked from commit 1eb08445d96a2c41593719925203f43f881b3567)

Autobuild-User(v4-6-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-6-test): Mon Dec 18 15:32:49 CET 2017 on sn-devel-144