ctdb-common: Add wait_send/wait_recv to sock_daemon_funcs

ctdb-common: Add wait_send/wait_recv to sock_daemon_funcs

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12510

To be able to terminate the daemon from within the implementation,
create a subreq using wait_send() provided by the implementation.
When the subreq is finished, it signals the sock_daemon code to terminate
the daemon.

This avoids the need to keep track of the top level tevent_req causing
layer violation and keeps the code flow straighforward.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Mon Jan 16 21:16:51 CET 2017 on sn-devel-144