Updated openstack/openstack
Project: openstack/python-glanceclient  e7b7cfe2f3545af6e2aeaba5e38063b19aef83b9
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Replace inheritance hierarchy with composition

In the process of unification of the clients code we should use
composition to allow easier replacement with common HTTPClient.

Related to blueprint common-client-library-2

Change-Id: I5addc38eb2e2dd0be91b566fda7c0d81787ffa75