Change oslo.utils to oslo_utils

The oslo.utils libraries are moving away from namespace packages.

This requires oslo.utils>=1.2.0

bp drop-namespace-packages

Change-Id: I803df61e91eabb96329d859aef6bea03530fb84f

glanceclient/common/https.py

@@ -26,7 +26,7 @@ except ImportError:
     from urllib3 import connectionpool
     from urllib3 import poolmanager
 
-from oslo.utils import encodeutils
+from oslo_utils import encodeutils
 import six
 
 from glanceclient.common import utils