Update to a newer hacking library

The older hacking library has a cap on pbr <2.0, with the recent 2.0.0
release of PBR it's causing failures in the pep8 job. See more details
here: https://bugs.launchpad.net/openstack-requirements/+bug/1668848

Change-Id: Ia2a08d917f2b4b5ed0c64b5bb208665b423c1cc1

distil/db/migration/alembic_migrations/versions/001_init_tables.py

@@ -107,4 +107,4 @@ def downgrade():
     op.drop_table('usage_entry')
     op.drop_table('resources')
     op.drop_table('distil_last_run')
-    op.drop_table('sales_orders')
+    op.drop_table('sales_orders')

distil/erp/driver.py

@@ -63,4 +63,4 @@ class BaseDriver(object):
 
         :param project: project
         """
-        raise NotImplementedError()
+        raise NotImplementedError()

distil/rater/__init__.py

@@ -37,4 +37,4 @@ def get_rater():
                                      CONF.rater.rater_type,
                                      invoke_on_load=True,
                                      invoke_kwds={}).driver
-    return RATER
+    return RATER

test-requirements.txt

@@ -1,4 +1,4 @@
-hacking>=0.9.2,<0.10
+hacking>=0.12.0,!=0.13.0,<0.14 # Apache-2.0
 coverage>=3.6
 discover
 fixtures>=0.3.14