Temporary disable Cinder scenario that creating volume from image

cinder job occurs error when downloading image, we temporarily
comment this task.

Change-Id: If50bf0ed09dc8f1046acefd2401fb90303613cc0

rally-jobs/cinder.yaml

@@ -149,31 +149,31 @@
         failure_rate:
           max: 0
 
-    -
-      args:
-        size: 1
-        image:
-          name: "image-context-test"
-      runner:
-        type: "constant"
-        times: 1
-        concurrency: 1
-      context:
-        users:
-          tenants: 1
-          users_per_tenant: 2
-        roles:
-          - admin
-        images:
-          image_url: "~/.rally/extra/fake-image.img"
-          disk_format: "qcow2"
-          container_format: "bare"
-          images_per_tenant: 1
-          image_name: "image-context-test"
-          visibility: "public"
-      sla:
-        failure_rate:
-          max: 0
+#    -
+#      args:
+#        size: 1
+#        image:
+#          name: "image-context-test"
+#      runner:
+#        type: "constant"
+#        times: 1
+#        concurrency: 1
+#      context:
+#        users:
+#          tenants: 1
+#          users_per_tenant: 2
+#        roles:
+#          - admin
+#        images:
+#          image_url: "~/.rally/extra/fake-image.img"
+#          disk_format: "qcow2"
+#          container_format: "bare"
+#          images_per_tenant: 1
+#          image_name: "image-context-test"
+#          visibility: "public"
+#      sla:
+#        failure_rate:
+#          max: 0
 
   CinderVolumes.create_and_update_volume:
     -