Add nova.exception.InvalidRPCConnectionReuse.
Add nova.exception.InvalidRPCConnectionReuse.

nova.rpc.common.ConnectionContext makes use of an exception that was not
defined.  This patch adds it.

Change-Id: Ibfbd2fc56dbcc36c8f271d5bc8c6e1db04ce8c93

citrix-openstack-build/oslo.versionedobjects,openstack/oslo.versionedobjects