[simulator] Automatic stopping of rpc-servers
[simulator] Automatic stopping of rpc-servers

This patch provide the sync flag:

  simulator.py rpc-client --sync call
  simulator.py rpc-client --sync fanout

The --sync values means next:
- call:   to send sync msg via rpc.call
- fanout: to broadcast sync msg via rpc.fanout to all servers on topic

When clients has sent all messages, the rpc-server will be stopped
automatically and dump statistics to a file (if --json-file is used).

This is much usefull than rough killing the process of the server in
benchmark frameworks.

Change-Id: I06fd8dbbcdc8b2b9f13029029f730b417ff128ce

ozamiatin/oslo.messaging,ozamiatin/oslo.messaging