Use neutron-lib portbindings api-def

This patch refactors networking-powervm to use portbindings
from neutron-lib. For more details see [1].

NeutronLibImpact

[1] https://review.openstack.org/422210/

Change-Id: I05588f7a9dd9f495d879c7ebcf70b2c5616c3a46

networking_powervm/plugins/ml2/drivers/mech_pvm_base.py

@@ -17,10 +17,10 @@
 import copy
 
 from neutron.common import topics
-from neutron.extensions import portbindings
 from neutron.plugins.ml2 import driver_api as api
 from neutron.plugins.ml2.drivers import mech_agent
 from neutron.plugins.ml2 import rpc
+from neutron_lib.api.definitions import portbindings
 from oslo_log import log
 
 LOG = log.getLogger(__name__)

networking_powervm/plugins/ml2/drivers/mech_pvm_sriov.py

@@ -14,8 +14,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.extensions import portbindings
 from neutron.plugins.common import constants as p_constants
+from neutron_lib.api.definitions import portbindings
 from oslo_log import log
 
 from networking_powervm.plugins.ibm.agent.powervm import constants as pconst

requirements.txt

@@ -16,4 +16,4 @@ oslo.utils>=3.18.0 # Apache-2.0
 oslo.config!=3.18.0,>=3.14.0 # Apache-2.0
 pypowervm
 setuptools!=24.0.0,>=16.0 # PSF/ZPL
-neutron-lib>=1.0.0 # Apache-2.0
+neutron-lib>=1.1.0 # Apache-2.0