bug: only use failure() on exceptions in write_error

Closes #1388

autopush/base.py

@@ -65,7 +65,7 @@ def write_error(self, code, **kwargs):
                     failure=failure.Failure(*kwargs['exc_info']),
                     client_info=self._client_info)
             else:
-                self.log.failure("Error in handler: %s" % code,
+                self.log.error("Error in handler: %s" % code,
                                  client_info=self._client_info)
             self.finish()
         except Exception as ex:

autopush/tests/test_web_base.py

@@ -147,10 +147,13 @@ def test_write_error_no_exc(self):
         with an invalid method (e.g. "put" instead of "PUT").
         This is not code that is triggered within normal flow, but
         by the cyclone wrapper.
+
+        NOTE: calling `failure` without an exception triggers an
+        exception. write_error should call `error`. 
         """
         self.base.write_error(999)
         self.status_mock.assert_called_with(999)
-        assert self.base.log.failure.called is True
+        assert self.base.log.error.called is True
 
     @patch('uuid.uuid4', return_value=uuid.UUID(dummy_request_id))
     def test_init_info(self, t):