[Fix gate]Update test requirement

Since pbr already landed and the old version of hacking seems not
work very well with pbr>=2, we should update it to match global
requirement.
Partial-Bug: #1668848

Change-Id: I5df54461c5edf8de3339869cbceef36633c87f69

test-requirements.txt

@@ -1,7 +1,7 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-hacking>=0.12.0,<0.13  # Apache-2.0
+hacking>=0.12.0,!=0.13.0,<0.14  # Apache-2.0
 flake8<2.6.0,>=2.5.4 # MIT
 nose # LGPL
 mock>=2.0 # BSD