Updated openstack/openstack
Project: openstack/ceilometer  8a5667de29b7b6c9583b1961178574dff11ee4ad

add keystone events to definitions

keystone events are not measurements and do not make much sense as
samples. this patch adds definition for keystone events.

Change-Id: I13b76a71cf434512190615266948293df4d34589
Partial-Bug: #1384874