Updated from global requirements

Change-Id: I6fc4356120cf0ddaa6a8d667d54a1f84c1a49e84
diff --git a/requirements.txt b/requirements.txt
index ffe6f26..17d063d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 pbr>=1.6
-cliff>=1.14.0 # Apache-2.0
+cliff>=1.15.0 # Apache-2.0
 anyjson>=0.3.3
 httplib2>=0.7.5
 jsonschema!=2.5.0,<3.0.0,>=2.0.0