Move ocata VCP nodes to preconfigured cloudinit images

VCP nodes require the preconfigured image because of reduced
mirrors that miss some packages.

Change-Id: I2bf119f5338ee50308fdaa1d28d86df318012037
diff --git a/tcp_tests/templates/virtual-mcp11-k8s-contrail/underlay.yaml b/tcp_tests/templates/virtual-mcp11-k8s-contrail/underlay.yaml
index af1b8e6..60094c7 100644
--- a/tcp_tests/templates/virtual-mcp11-k8s-contrail/underlay.yaml
+++ b/tcp_tests/templates/virtual-mcp11-k8s-contrail/underlay.yaml
@@ -141,7 +141,10 @@
 
         group_volumes:
          - name: cloudimage1604    # This name is used for 'backing_store' option for node volumes.
-           source_image: !os_env IMAGE_PATH1604  # https://cloud-images.ubuntu.com/xenial/current/xenial-server-cloudimg-amd64-disk1.img
+           # http://images.mirantis.com/ubuntu-16-04-x64-latest.qcow2  (preffered)
+           # or
+           # https://cloud-images.ubuntu.com/xenial/current/xenial-server-cloudimg-amd64-disk1.img
+           source_image: {{ os_env('MCP_IMAGE_PATH1604', os_env('IMAGE_PATH1604')) }}
            format: qcow2
 
          - name: cfg01_day01_image               # Pre-configured day01 image