Update hacking to fix pep8 failure

With the release of pbr 1.0.0, we need a newer version of hacking.
Update the version. hacking is manually synced from global
requirements repo, use the version from there.

See also
http://lists.openstack.org/pipermail/openstack-dev/2015-May/064362.html

Change-Id: Ic3ff9ad74acd57fe149e5873fefe8a99e1d701d8

test-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.
 
-hacking>=0.9.2,<0.10
+hacking>=0.10.0,<0.11
 
 # this is required for the docs build jobs
 sphinx>=1.1.2,!=1.2.0,!=1.3b1,<1.3