Use network 'heat-net' for integration_tests

Neutron support for ipv6 is not complete yet (ex. LBaaS
only supports ipv4). We'had some gate issues after dual
stack was enabled in devstack. We had put some tactical
fixes to resolve those[1][2].

This fix adds usage of heat-net/heat-subnet(only ipv4)
for integration tests. This also rolls back the earlier
tactical changes.

https://review.openstack.org/#/c/178576
https://review.openstack.org/#/c/178933/

Change-Id: Ia863edb8932b8dea5c4fa110c97dcfdadca85bb9
diff --git a/scenario/templates/test_neutron_autoscaling.yaml b/scenario/templates/test_neutron_autoscaling.yaml
index 59aad2c..a34ec43 100644
--- a/scenario/templates/test_neutron_autoscaling.yaml
+++ b/scenario/templates/test_neutron_autoscaling.yaml
@@ -11,7 +11,7 @@
     type: string
     label: Capacity
     description: Auto-scaling group desired capacity
-  fixed_subnet_name:
+  fixed_subnet:
     type: string
     label: fixed subnetwork ID
     description: subnetwork ID used for autoscaling
@@ -28,7 +28,7 @@
       lb_method: ROUND_ROBIN
       name: test_pool
       protocol: HTTP
-      subnet: { get_param: fixed_subnet_name }
+      subnet: { get_param: fixed_subnet }
       vip: {
         "description": "Test VIP",
         "protocol_port": 80,
@@ -49,6 +49,7 @@
     properties:
       AvailabilityZones : ["nova"]
       LaunchConfigurationName : { get_resource : launch_config }
+      VPCZoneIdentifier: [{ get_param: fixed_subnet }]
       MinSize : 1
       MaxSize : 5
       DesiredCapacity: { get_param: capacity }