azure: append .vhd to name of blobs written during image build process.

Azure publishing portal requires input blob names to end in .vhd.

playbooks/azure/openshift-cluster/tasks/create_blob_from_vm.yml

@@ -27,7 +27,7 @@
     --account-name "{{ openshift_azure_storage_account }}"
     --account-key "{{ (keys.stdout | from_json)[0].value }}"
     --destination-container "{{ openshift_azure_container }}"
-    --destination-blob "{{ image_name }}"
+    --destination-blob "{{ image_name }}.vhd"
 
 - name: get copy status
   command: >
@@ -35,7 +35,7 @@
     --account-name "{{ openshift_azure_storage_account }}"
     --account-key "{{ (keys.stdout | from_json)[0].value }}"
     --container-name "{{ openshift_azure_container }}"
-    --name "{{ image_name }}"
+    --name "{{ image_name }}.vhd"
     --query "properties.copy.status"
   register: status
   until: status.stdout | from_json == "success"