Some updates to object_store user guide
Some updates to object_store user guide

There were a few outdated mentions in there from the old version of the
proxy.

Change-Id: Ibd020d2c06b6489808f8bcc5570a9cb251a11146

openstack/python-openstacksdk,dudymas/python-openstacksdk,briancurtin/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk,openstack/python-openstacksdk,stackforge/python-openstacksdk,mtougeron/python-openstacksdk,mtougeron/python-openstacksdk,dudymas/python-openstacksdk,briancurtin/python-openstacksdk,dtroyer/python-openstacksdk