TST: mark gbq streaming insert tests as slow

Author: jreback

ci/requirements-3.4_SLOW.pip

@@ -0,0 +1,3 @@
+httplib2
+google-api-python-client
+oauth2client

pandas/io/tests/test_gbq.py

@@ -938,6 +938,7 @@ def test_upload_data_if_table_exists_replace(self):
                               private_key=_get_private_key_path())
         self.assertEqual(result['NUM_ROWS'][0], 5)
 
+    @tm.slow
     def test_google_upload_errors_should_raise_exception(self):
         destination_table = DESTINATION_TABLE + "5"