use rpc from neutron-lib

We recently removed nenutron.common.rpc [1] as the rpc module lives in
neutron-lib now. This project was missed because I didn't find
neutron.common.rpc as an import.

This patch switches rpc uses over to neutron-lib.

[1] https://review.openstack.org/#/c/634790/

This commit includes a part of the following commit
to pass the gate.
----------------------------------------
Fix zuul job failures

Fix zuul job failures

Change-Id: I1d073b8c58e32669ecf6932512b94c8a2cabf70e
----------------------------------------

Co-Authored-By: Deepak Tiwari <deepak.tiwari@aricent.com>
Change-Id: I053b5c56594e1a914143a2308fef77349dfa7ea4

neutron_taas/tests/unit/services/taas/test_taas_plugin.py

@@ -19,11 +19,11 @@ import mock
 import testtools
 
 from neutron_lib import context
+from neutron_lib import rpc as n_rpc
 from neutron_lib.utils import net as n_utils
 from oslo_config import cfg
 from oslo_utils import uuidutils
 
-import neutron.common.rpc as n_rpc
 from neutron.tests.unit import testlib_api
 
 import neutron_taas.db.taas_db  # noqa

tox.ini

@@ -12,6 +12,7 @@ deps = -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/re
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands = find . -type f -name "*.py[c|o]" -delete
+           find . -type l -name "*.py[c|o]" -delete
            find . -type d -name "__pycache__" -delete
            ostestr --regex '{posargs}'
 whitelist_externals = find