Glance notifications documentation does not list all possible event groups

[Alexander Bashmakov]

The notifications reference in Glance developer docs currently only lists: image.* and task.* events. There are a number of other event types that can be emitted by the service:

        * image.member
        * metadef_namespace
        * metadef_object
        * metadef_property
        * metadef_resource_type
        * metadef_tag

These all need to be properly documented here: http://docs.openstack.org/developer/glance/notifications.html.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/358550

[OpenStack Infra (hudson-openstack)]

Change abandoned by Kairat Kushaev (<email address hidden>) on branch: master
Review: https://review.openstack.org/358550