Fixing credentials without scopes issue in logging.

See:
https://travis-ci.org/GoogleCloudPlatform/google-cloud-python/builds/191433056#L2195

This is a band-aid for now. I caused it in googleapis#2875 and will roll-back this
roll-back at a later time.

@daspecter fixed a similar breakage in googleapis#2909.

logging/google/cloud/logging/_gax.py

@@ -532,7 +532,7 @@ def make_gax_logging_api(client):
     :returns: A metrics API instance with the proper credentials.
     """
     channel = make_secure_channel(
-        client._credentials, DEFAULT_USER_AGENT,
+        client._connection.credentials, DEFAULT_USER_AGENT,
         LoggingServiceV2Client.SERVICE_ADDRESS)
     generated = LoggingServiceV2Client(channel=channel)
     return _LoggingAPI(generated, client)
@@ -548,7 +548,7 @@ def make_gax_metrics_api(client):
     :returns: A metrics API instance with the proper credentials.
     """
     channel = make_secure_channel(
-        client._credentials, DEFAULT_USER_AGENT,
+        client._connection.credentials, DEFAULT_USER_AGENT,
         MetricsServiceV2Client.SERVICE_ADDRESS)
     generated = MetricsServiceV2Client(channel=channel)
     return _MetricsAPI(generated, client)
@@ -564,7 +564,7 @@ def make_gax_sinks_api(client):
     :returns: A metrics API instance with the proper credentials.
     """
     channel = make_secure_channel(
-        client._credentials, DEFAULT_USER_AGENT,
+        client._connection.credentials, DEFAULT_USER_AGENT,
         ConfigServiceV2Client.SERVICE_ADDRESS)
     generated = ConfigServiceV2Client(channel=channel)
     return _SinksAPI(generated, client)

logging/google/cloud/logging/handlers/transports/background_thread.py

@@ -152,7 +152,7 @@ class BackgroundThreadTransport(Transport):
     def __init__(self, client, name):
         http = copy.deepcopy(client._http)
         self.client = client.__class__(
-            client.project, client._credentials, http)
+            client.project, client._connection.credentials, http)
         logger = self.client.logger(name)
         self.worker = _Worker(logger)
 

logging/unit_tests/handlers/transports/test_background_thread.py

@@ -170,9 +170,13 @@ def batch(self):
 class _Client(object):
 
     def __init__(self, project, http=None, credentials=None):
+        import mock
+
         self.project = project
         self._http = http
         self._credentials = credentials
+        self._connection = mock.Mock(
+            credentials=credentials, spec=['credentials'])
 
     def logger(self, name):  # pylint: disable=unused-argument
         self._logger = _Logger(name)

logging/unit_tests/test__gax.py

@@ -1085,7 +1085,8 @@ def test_it(self):
         from google.cloud.logging._gax import DEFAULT_USER_AGENT
 
         creds = object()
-        client = mock.Mock(_credentials=creds)
+        conn = mock.Mock(credentials=creds, spec=['credentials'])
+        client = mock.Mock(_connection=conn, spec=['_connection'])
         channels = []
         channel_args = []
         channel_obj = object()
@@ -1130,7 +1131,8 @@ def test_it(self):
         from google.cloud.logging._gax import DEFAULT_USER_AGENT
 
         creds = object()
-        client = mock.Mock(_credentials=creds)
+        conn = mock.Mock(credentials=creds, spec=['credentials'])
+        client = mock.Mock(_connection=conn, spec=['_connection'])
         channels = []
         channel_args = []
         channel_obj = object()
@@ -1175,7 +1177,8 @@ def test_it(self):
         from google.cloud.logging._gax import DEFAULT_USER_AGENT
 
         creds = object()
-        client = mock.Mock(_credentials=creds)
+        conn = mock.Mock(credentials=creds, spec=['credentials'])
+        client = mock.Mock(_connection=conn, spec=['_connection'])
         channels = []
         channel_args = []
         channel_obj = object()