Reorganize the code to satisfy review comments.

nova/rpc/__init__.py

@@ -18,12 +18,12 @@
 
 
 from nova.utils import import_object
-from nova.rpc_backends.common import RemoteError, LOG
+from nova.rpc.common import RemoteError, LOG
 from nova import flags
 
 FLAGS = flags.FLAGS
 flags.DEFINE_string('rpc_backend',
-                    'nova.rpc_backends.amqp',
+                    'nova.rpc.amqp',
                     "The messaging module to use, defaults to AMQP.")
 
 RPCIMPL = import_object(FLAGS.rpc_backend)

nova/rpc/amqp.py

@@ -44,7 +44,7 @@ from nova import fakerabbit
 from nova import flags
 from nova import log as logging
 from nova import utils
-from nova.rpc_backends.common import RemoteError, LOG
+from nova.rpc.common import RemoteError, LOG
 
 
 FLAGS = flags.FLAGS

nova/tests/test_rpc_amqp.py

@@ -2,7 +2,7 @@ from nova import context
 from nova import flags
 from nova import log as logging
 from nova import rpc
-from nova.rpc_backends import amqp
+from nova.rpc import amqp
 from nova import test