fix tox tool

Author: caberos

tests/managers/network_tests.py

@@ -327,7 +327,6 @@ def test_list_subnets_with_filters(self):
 
         self.assertEqual(result, fixtures.SoftLayer_Account.getSubnets)
 
-
         self.assert_called_with('SoftLayer_Account', 'getSubnets',
                                 mask='mask[%s]' % network.DEFAULT_SUBNET_MASK)