Add image dependencies test for image <-> instance snapshot

Detect problems related to Glance images not allowing
Glance images to be deleted.

Adds new option:
  CONF.volume_feature_enabled.enable_volume_image_dep_tests

Change-Id: Ia216f5be377bf5c35d7addb78d7f8aabb2393405
diff --git a/releasenotes/notes/add-enable-volume-image-dep-tests-option-150b929d18da233f.yaml b/releasenotes/notes/add-enable-volume-image-dep-tests-option-150b929d18da233f.yaml
new file mode 100644
index 0000000..979f083
--- /dev/null
+++ b/releasenotes/notes/add-enable-volume-image-dep-tests-option-150b929d18da233f.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Add new config option 'enable-volume-image-dep-tests' in section
+    [volume-feature-enabled] which should be used in
+    image<->volume<->snapshot dependency tests.