ctdb: when we fill the client packet queue we need to drop the client

ctdb: when we fill the client packet queue we need to drop the client

We can't just drop packets to the list, as those packets could be part
of the core protocol the client is using. This happens (for example)
when Samba is doing a traverse. If we drop a traverse packet then
Samba hangs indefinately. We are better off dropping the ctdb socket
to Samba.