Fix unit test test_new_subnet_installed_order_ports_router_dp failure
Fix unit test test_new_subnet_installed_order_ports_router_dp failure

Change-Id: Ib4e13ae9421ac524f2f06c9e8d9d1c46c96821b7

no2key/dragonflow,no2key/dragonflow,FrankDuan/df_code,neoareslinux/dragonflow,openstack/dragonflow,FrankDuan/df_code,openstack/dragonflow,FrankDuan/df_code,openstack/dragonflow,neoareslinux/dragonflow