Fix enable-volume-image-dep-tests config option

Replaced hyphen with underscore in config option

Change-Id: I5a34b57809fe2b3ef94e3b4b2ae3a6ea23003c0f
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
index 979f083..e78201e 100644
--- a/releasenotes/notes/add-enable-volume-image-dep-tests-option-150b929d18da233f.yaml
+++ b/releasenotes/notes/add-enable-volume-image-dep-tests-option-150b929d18da233f.yaml
@@ -1,6 +1,6 @@
 ---
 features:
   - |
-    Add new config option 'enable-volume-image-dep-tests' in section
+    Add new config option 'enable_volume_image_dep_tests' in section
     [volume-feature-enabled] which should be used in
     image<->volume<->snapshot dependency tests.
diff --git a/tempest/config.py b/tempest/config.py
index abab70f..4b5330a 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -1071,7 +1071,7 @@
                default=None,
                help='Volume types used for data volumes. Multiple volume '
                     'types can be assigned.'),
-    cfg.BoolOpt('enable-volume-image-dep-tests',
+    cfg.BoolOpt('enable_volume_image_dep_tests',
                 default=True,
                 help='Run tests for dependencies between images, volumes'
                 'and instance snapshots')