Disable message dispatching when send rule result is not known

Disable message dispatching when send rule result is not known

When unicast message to addressed recipient is sent and policy result
is not available message dispatch from the sender is disabled.
This also means that any further messages from the given connection are
put into the incoming queue. If response is received message dispatching
is resumed. This time answer is expected to be in cache so the message is
processed synchronously.
Receive rule result unavailability is not yet handled - such messages are
rejected. Also, if message is sent to non-addressed recipient message
is silently dropped.

Change-Id: Ia45905baf667ca42f386c1def108eca190d615bb