switch from mox to mox3

Mox3 is an unofficial port of the Google mox framework to Python 3.

Closes-bug: 1283482
Change-Id: I3f558420bc720880eb91fca7b936bdcd6949a513

test-requirements.txt

@@ -13,7 +13,7 @@ wsgi_intercept>=0.6.1 # MIT License
 proboscis==1.2.5.3
 http://tarballs.openstack.org/python-troveclient/python-troveclient-master.tar.gz#egg=python-troveclient
 mock>=1.0
-mox>=0.5.3
+mox3>=0.7.0
 testtools>=0.9.34
 discover
 testrepository>=0.0.18

trove/tests/api/instances_resize.py

@@ -13,8 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mox
 from mock import Mock
+from mox3 import mox
 from testtools import TestCase
 from proboscis import test
 

trove/tests/api/mgmt/instances_actions.py

@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mox
+from mox3 import mox
 import trove.common.instance as tr_instance
 from trove.backup import models as backup_models
 from trove.common.context import TroveContext