[DM]: Fix for recent regression issue, ip_alloc param issue

This is regression issue introduced after changing the prototype of ip_alloc API.

Change-Id: Icff7f9bb1b404863d2912adc99b82b1ac8d0a59e
Closes-Bug: #1646344

src/config/device-manager/device_manager/db.py

@@ -216,7 +216,7 @@ def reserve_ip(self, vn_uuid, subnet_uuid):
             vn.set_uuid(vn_uuid)
             ip_addr = self._manager._vnc_lib.virtual_network_ip_alloc(
                 vn,
-                subnet_uuid=subnet_uuid)
+                subnet=subnet_uuid)
             if ip_addr:
                 return ip_addr[0]  # ip_alloc default ip count is 1
         except Exception as e:
@@ -286,6 +286,7 @@ def evaluate_vn_irb_ip_map(self, vn_set):
 
         for vn_subnet in create_set:
             (vn_uuid, subnet_prefix) = vn_subnet.split(':', 1)
+            vn = VirtualNetworkDM.get(vn_uuid)
             subnet_uuid = vn.gateways[subnet_prefix].get('subnet_uuid')
             (sub, length) = subnet_prefix.split('/')
             ip_addr = self.reserve_ip(vn_uuid, subnet_uuid)