use common rpc and exceptions from neutron-lib

The neutron.common.rpc and exceptions were rehomed into neutron-lib and
are currently shimmed in neutron [1]

This patch consumes those modules from neutron-lib by using lib's
modules rather than neutrons.

[1] https://review.openstack.org/#/c/586525/

Change-Id: Ic95e9ab17fa6ba3b12cea7837322f113d0084aeb

neutron_dynamic_routing/api/rpc/agentnotifiers/bgp_dr_rpc_agent_api.py

@@ -13,10 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from neutron_lib import rpc as n_rpc
 import oslo_messaging
 
-from neutron.common import rpc as n_rpc
-
 from neutron_dynamic_routing.services.bgp.common import constants as bgp_consts
 
 

neutron_dynamic_routing/services/bgp/agent/bgp_dragent.py

@@ -18,6 +18,7 @@ import collections
 from neutron_lib.agent import constants as agent_consts
 from neutron_lib.agent import topics
 from neutron_lib import context
+from neutron_lib import rpc as n_rpc
 from neutron_lib.utils import runtime
 from oslo_config import cfg
 from oslo_log import log as logging
@@ -27,7 +28,6 @@ from oslo_service import periodic_task
 from oslo_utils import importutils
 
 from neutron.agent import rpc as agent_rpc
-from neutron.common import rpc as n_rpc
 from neutron.common import utils
 from neutron import manager
 

neutron_dynamic_routing/services/bgp/bgp_plugin.py

@@ -19,13 +19,12 @@ from neutron_lib.callbacks import registry
 from neutron_lib.callbacks import resources
 from neutron_lib import constants as n_const
 from neutron_lib import context
+from neutron_lib import rpc as n_rpc
 from neutron_lib.services import base as service_base
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import importutils
 
-from neutron.common import rpc as n_rpc
-
 from neutron_dynamic_routing.api.rpc.agentnotifiers import bgp_dr_rpc_agent_api  # noqa
 from neutron_dynamic_routing.api.rpc.callbacks import resources as dr_resources
 from neutron_dynamic_routing.api.rpc.handlers import bgp_speaker_rpc as bs_rpc