[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: I1af28a757450789f0f523847831b42e016f785fd

test-requirements.txt

 # 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<0.11,>=0.10.0
+hacking>=0.12.0,!=0.13.0,<0.14  # Apache-2.0
 oslotest>=1.10.0 # Apache-2.0
 testtools>=1.4.0 # MIT
 # These are needed for docs generation