Fix AttributeError in RPC code for DVR

Fix the usage of call methods as per recent changes according to
drop-rpc-compat. These changes went overlooked and it broke DVR.

Tests will be done as follow-up.

Partial-bug: #1394848

Change-Id: I6e0584f8e54e606a76b87853b2371cc8e24eba69

neutron/api/rpc/handlers/dvr_rpc.py

@@ -30,32 +30,24 @@ class DVRServerRpcApiMixin(object):
 
     @log.log
     def get_dvr_mac_address_by_host(self, context, host):
-        return self.call(context,
-                         self.make_msg('get_dvr_mac_address_by_host',
-                                       host=host),
-                         version=self.DVR_RPC_VERSION)
+        cctxt = self.client.prepare(version=self.DVR_RPC_VERSION)
+        return cctxt.call(context, 'get_dvr_mac_address_by_host', host=host)
 
     @log.log
     def get_dvr_mac_address_list(self, context):
-        return self.call(context,
-                         self.make_msg('get_dvr_mac_address_list'),
-                         version=self.DVR_RPC_VERSION)
+        cctxt = self.client.prepare(version=self.DVR_RPC_VERSION)
+        return cctxt.call(context, 'get_dvr_mac_address_list')
 
     @log.log
     def get_ports_on_host_by_subnet(self, context, host, subnet):
-        return self.call(context,
-                         self.make_msg(
-                             'get_ports_on_host_by_subnet',
-                             host=host,
-                             subnet=subnet),
-                         version=self.DVR_RPC_VERSION)
+        cctxt = self.client.prepare(version=self.DVR_RPC_VERSION)
+        return cctxt.call(context, 'get_ports_on_host_by_subnet',
+                          host=host, subnet=subnet)
 
     @log.log
     def get_subnet_for_dvr(self, context, subnet):
-        return self.call(context,
-                         self.make_msg('get_subnet_for_dvr',
-                                       subnet=subnet),
-                         version=self.DVR_RPC_VERSION)
+        cctxt = self.client.prepare(version=self.DVR_RPC_VERSION)
+        return cctxt.call(context, 'get_subnet_for_dvr', subnet=subnet)
 
 
 class DVRServerRpcCallback(object):

neutron/services/firewall/agents/l3reference/firewall_l3_agent.py

@@ -38,18 +38,15 @@ def __init__(self, topic, host):
     def get_firewalls_for_tenant(self, context, **kwargs):
         """Get the Firewalls with rules from the Plugin to send to driver."""
         LOG.debug("Retrieve Firewall with rules from Plugin")
-
-        return self.call(context,
-                         self.make_msg('get_firewalls_for_tenant',
-                                       host=self.host))
+        cctxt = self.client.prepare()
+        return cctxt.call(context, 'get_firewalls_for_tenant', host=self.host)
 
     def get_tenants_with_firewalls(self, context, **kwargs):
         """Get all Tenants that have Firewalls configured from plugin."""
         LOG.debug("Retrieve Tenants with Firewalls configured from Plugin")
-
-        return self.call(context,
-                         self.make_msg('get_tenants_with_firewalls',
-                                       host=self.host))
+        cctxt = self.client.prepare()
+        return cctxt.call(context,
+                          'get_tenants_with_firewalls', host=self.host)
 
 
 class FWaaSL3AgentRpcCallback(api.FWaaSAgentRpcCallbackMixin):