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: Ifb87c315953a02291201a25aff05910149023d10

neutron_taas/services/taas/agents/ovs/taas_ovs_agent.py

@@ -14,12 +14,12 @@
 # under the License.
 
 
-from neutron.common import rpc as n_rpc
 from neutron import manager
 
 from neutron_taas.common import topics
 from neutron_taas.services.taas.agents import taas_agent_api as api
 
+from neutron_lib import rpc as n_rpc
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_service import service

neutron_taas/services/taas/agents/taas_agent_api.py

@@ -13,11 +13,11 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from neutron_lib import rpc as n_rpc
 from neutron_taas._i18n import _
 from oslo_config import cfg
 import oslo_messaging as messaging
 
-from neutron.common import rpc as n_rpc
 
 TaasOpts = [
     cfg.StrOpt(

neutron_taas/services/taas/service_drivers/taas_agent_api.py

@@ -14,8 +14,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from neutron.common import rpc as n_rpc
-
+from neutron_lib import rpc as n_rpc
 from oslo_log import log as logging
 import oslo_messaging as messaging
 

neutron_taas/services/taas/service_drivers/taas_rpc.py

@@ -14,8 +14,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from neutron.common import rpc as n_rpc
 from neutron_lib import exceptions as n_exc
+from neutron_lib import rpc as n_rpc
 from neutron_taas.common import topics
 from neutron_taas.services.taas import service_drivers
 from neutron_taas.services.taas.service_drivers import taas_agent_api