dbwrap_ctdb: Use messaging_ctdbd_connection

dbwrap_ctdb: Use messaging_ctdbd_connection

With messages_ctdb, the global ctdb connection will change after fork.

Don't store the wrong parent connection across a fork. The alternative would
be to do a reinit on all dbwrap_ctdb databases, but that seems overkill
given that we only have one "standard" ctdb connection anyway.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>