Fix import statement order

Fix import statement order to comply with
OpenStack Style Guidelines(*1).

*1: http://docs.openstack.org/developer/hacking/#import-order-template

TrivialFix
Change-Id: I8ded09c14396a46f9d0f8f565d1294b179ce09bc

nova/tests/functional/regressions/test_bug_1595962.py

@@ -12,9 +12,10 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import time
+
 import fixtures
 import mock
-import time
 
 import nova.conf
 from nova import test