Fixed a typo in the rst docs.
Fixed a typo in the rst docs.

Change-Id: Ie3484f8fe0a63ff5a6815f3ec440adf7dc5d9482

dtroyer/python-openstackclient,redhat-openstack/python-openstackclient,derekchiang/python-openstackclient,varunarya10/python-openstackclient,openstack/python-openstackclient,derekchiang/python-openstackclient,BjoernT/python-openstackclient,dtroyer/python-openstackclient,BjoernT/python-openstackclient,redhat-openstack/python-openstackclient,citrix-openstack-build/python-openstackclient,citrix-openstack-build/python-openstackclient,metacloud/python-openstackclient,openstack/python-openstackclient,hughsaunders/python-openstackclient,metacloud/python-openstackclient,hughsaunders/python-openstackclient,varunarya10/python-openstackclient