Sync latest rpc changes from oslo-incubator

Includes these commits:

 99b7c35 Convert kombu SSL version string into integer
 1a2df89 Enable H302 hacking check
 3969355 Fix exception arg typo
 3006787 Sanitize passwords in _safe_log
 323e465 Add conditional exception reraise
 dea334a Replace sys.exit by a RPCException
 719eba4 Don't reconnect to exclusive fanout consumers.
 22ec8ff Make AMQP based RPC consumer threads more robust
 13650b1 rpc: remove some unused serialization code
 e204885 Optionally reject messages on exception.
 688832f Remove unused zmq relay functionality

The sslutils module is included for its validate_ssl_version() method.

Change-Id: Ic2b64f68bfda0dde365221ab1efbc592b1e5bc6f
Merge "Sync latest rpc changes from oslo-incubator"