[stable-only] Set volume_image_dep_tests flag

Change I5fee23951958fc00 to cinder-tempest-plugin adds volume<->image
dependency tests that the Bobcat and earlier rbd driver cannot pass,
so until the necessary rbd driver changes are backported, we need to
turn off those tests on jobs using Ceph.

Change-Id: Ida966ba08e6ad53b31b934d55859736c0db4871b

.zuul.yaml

@@ -177,6 +177,7 @@
           $TEMPEST_CONFIG:
             volume-feature-enabled:
               volume_revert: True
+              volume_image_dep_tests: False
     timeout: 10800
 
 - job:
@@ -214,6 +215,10 @@
           $CINDER_CONF:
             DEFAULT:
               cluster: ceph
+        test-config:
+          $TEMPEST_CONFIG:
+            volume-feature-enabled:
+              volume_image_dep_tests: False
 
 - job:
     name: cinder-grenade-mn-sub-bak