Fix vision failure on Python 3

Change-Id: Ieb53e6cdd8b1a70089b970b7a2aa57dd3d24c3de

Author: Jon Wayne Parrott

vision/cloud-client/quickstart_test.py

@@ -12,9 +12,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
+import six
+
 import quickstart
 
 
+@pytest.mark.xfail(
+    six.PY3,
+    strict=True,
+    reason='https://github.com/GoogleCloudPlatform/google-cloud-python/issues'
+           '/2525')
 def test_quickstart(capsys):
     quickstart.run_quickstart()
     out, _ = capsys.readouterr()