Fix indentation in releasenotes

This commit fixes indentations in releasenotes. Due to the indentations,
the html contents are rendered as block quotes which is awkward.

Change-Id: Ia9f271ead6a6e3fb90afc935771e8da4d8990c3c
diff --git a/releasenotes/notes/15/15.0.0-add-image-clients-tests-49dbc0a0a4281a77.yaml b/releasenotes/notes/15/15.0.0-add-image-clients-tests-49dbc0a0a4281a77.yaml
index eaab1f0..a4e5791 100644
--- a/releasenotes/notes/15/15.0.0-add-image-clients-tests-49dbc0a0a4281a77.yaml
+++ b/releasenotes/notes/15/15.0.0-add-image-clients-tests-49dbc0a0a4281a77.yaml
@@ -5,6 +5,6 @@
     http://developer.openstack.org/api-ref/image/v2/metadefs-index.html,
     there are some apis are not included, add them.
 
-      * namespace_objects_client(v2)
-      * namespace_tags_client(v2)
+    * namespace_objects_client(v2)
+    * namespace_tags_client(v2)