Update hacking to 0.10.x series

Get current release of hacking both for new features/rules and to
address a problem where older hacking requires and older version of pbr
than the version of pbr under test. This will get the pep8 jobs working
again for pbr by removing the <1.0 pbr requirement in hacking.

Change-Id: I303db998e3aa64468a931f7e8985592b3446a1c8

test-requirements.txt

@@ -1,7 +1,7 @@
 coverage>=3.6
 discover
 fixtures>=0.3.14
-hacking>=0.9.2,<0.10
+hacking>=0.10.0,<0.11
 mock>=1.0
 python-subunit>=0.0.18
 sphinx>=1.1.2,<1.2