Catch new urllib3 exception: ProtocolError

The new version of requests (2.4.0) has updated underlying urllib3
to version 1.9. Unfortunately urllib3 introduced new exception
ProtocolError. Because of that unit tests in glance are failing:
ProtocolError: ('Connection aborted.', gaierror(-2, 'Name or service not known'))

To solve this problem new urllib3 exception is caught in the same place
that the old one was. Unfortunately both exception are still in use so
I couldn't remove the old one.

Change-Id: I55eef98e734c59b9b627f182768a633b2b701e43
Closes-Bug: #1364893

glanceclient/common/http.py

@@ -18,6 +18,10 @@ import logging
 import socket
 
 import requests
+try:
+    from requests.packages.urllib3.exceptions import ProtocolError
+except ImportError:
+    ProtocolError = requests.exceptions.ConnectionError
 import six
 from six.moves.urllib import parse
 
@@ -198,7 +202,7 @@ class HTTPClient(object):
             message = ("Error communicating with %(endpoint)s %(e)s" %
                        dict(url=conn_url, e=e))
             raise exc.InvalidEndpoint(message=message)
-        except requests.exceptions.ConnectionError as e:
+        except (requests.exceptions.ConnectionError, ProtocolError) as e:
             message = ("Error finding address for %(url)s: %(e)s" %
                        dict(url=conn_url, e=e))
             raise exc.CommunicationError(message=message)