Fix service start sequence

1. zmq-receiver should be started in advance
2. when using zeromq driver, nova-compute relies
on nova-conductor's rpc to be initialized

This fix is totally safe and won't influence
on other services.

Change-Id: I9d7b682df4d411af24a1ff6bcad79697e32fa723
Partially-Implements: blueprint zeromq
diff --git a/lib/nova b/lib/nova
index cbfbdfa..5ac9ff1 100644
--- a/lib/nova
+++ b/lib/nova
@@ -769,8 +769,8 @@
 }
 
 function start_nova {
-    start_nova_compute
     start_nova_rest
+    start_nova_compute
 }
 
 function stop_nova_compute {