remove unnecessary code

As Ib6e76f34875431ce0dd106a1ff3d8ea1e42b6365 says, we should use
keystoneauth1.exceptions.EndpointNotFound instead of keystoneclient,
actually the one in ceilometer/tests/functional/api/v2/test_api_upgrade.py
is not needed at all, because we never call url_for() with other
values so far, we can simply remove the code.

Change-Id: I08dc24efc1c21aa931b7f66b1093f1be9ac8944f

ceilometer/keystone_client.py

@@ -15,7 +15,6 @@
 
 import os
 
-
 from keystoneauth1 import exceptions as ka_exception
 from keystoneauth1 import identity as ka_identity
 from keystoneauth1 import loading as ka_loading

ceilometer/tests/functional/api/v2/test_api_upgrade.py

@@ -11,7 +11,6 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from keystoneclient import exceptions
 import mock
 from oslotest import mockpatch
 
@@ -43,7 +42,6 @@ class TestAPIUpgradePath(v2.FunctionalTest):
             return 'http://gnocchi/'
         elif service_type == 'alarming':
             return 'http://alarm-endpoint:8008/'
-        raise exceptions.EndpointNotFound()
 
     def _do_test_gnocchi_enabled_without_database_backend(self):
         self.CONF.set_override('meter_dispatchers', 'gnocchi')