Add explicit check for rpc is not None

This change tests for the rpc value passed to the driver to be not None.
The explicity check does not change the logic and avoid a difference in
Python 2 vs Python 3 to resolve the boolean value of an object. Python 2
calls __nonzero__() to get boolean value of an object and Python 3
calls __boolean__().

Change-Id: I50a228840735bc1a7b0d857d0b28e01b4f836aef

networking_arista/ml2/mechanism_arista.py

@@ -77,7 +77,7 @@ class AristaDriver(driver_api.MechanismDriver):
 
         self.eapi = None
 
-        if rpc:
+        if rpc is not None:
             LOG.info("Using passed in parameter for RPC")
             self.rpc = rpc
             self.eapi = rpc

networking_arista/tests/unit/ml2/test_mechanism_arista.py

@@ -378,7 +378,6 @@ class AristaDriverTestCase(testlib_api.SqlTestCase):
 
         expected_calls = [
             mock.call.NeutronNets(),
-            mock.call.__nonzero__(),
             mock.call.is_port_provisioned(port_id),
             mock.call.is_network_provisioned(tenant_id, network_id, None),
             mock.call.plug_port_into_network(device_id, host_id, port_id,
@@ -525,7 +524,6 @@ class AristaDriverTestCase(testlib_api.SqlTestCase):
 
         expected_calls = [
             mock.call.NeutronNets(),
-            mock.call.__nonzero__(),
             mock.call.get_physical_network(host_id),
             mock.call.is_network_provisioned(tenant_id, network_id, None,
                                              None),
@@ -633,7 +631,6 @@ class AristaDriverTestCase(testlib_api.SqlTestCase):
 
         expected_calls = [
             mock.call.NeutronNets(),
-            mock.call.__nonzero__(),
             mock.call.is_network_provisioned(tenant_id, network_id,
                                              segmentation_id,
                                              segment_id),
@@ -801,7 +798,6 @@ class AristaDriverTestCase(testlib_api.SqlTestCase):
 
         expected_calls = [
             mock.call.NeutronNets(),
-            mock.call.__nonzero__(),
             mock.call.is_port_provisioned(port_id, None),
             mock.call.is_network_provisioned(tenant_id, network_id,
                                              None, None),