Comment 16 for bug 771512

Linked lp:~cbehrens/nova/rpc-improvements here also. This implements a connection pool for connections to rabbit, as well as changes the 3 Service topic consumers to use a single connection that has a single wait() for events. That eliminates 3 threads that are reach repeatedly polling rabbit every 0.1 seconds.

All of that should:

1) Reduce bombing rabbit with new connections
2) Reduce overall number of connections to rabbit
3) Reduce a lot of context switches
4) Remove possible unnecessary 0.1 second delay in services processing requests.

etc.