Don't pop from os.environ
Don't pop from os.environ

It's rude to other users and subsequent callers.

Change-Id: I7789f381c99311bfd1c1e0a9869cbacbc96b17d6

stackforge/python-openstacksdk,dtroyer/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk,openstack/python-openstacksdk,openstack/os-client-config,openstack/python-openstacksdk,dtroyer/os-client-config