Updated openstack/openstack
Project: openstack/ceilometer  716ff9e6536b872fa0357eeb17ffb5e21642d2d3

clean up event model

- fix defined relationships so they are properly backref
- fix trait_type __repr__ function to reference correct variable

Change-Id: Id606025ca3e91c6e9b7da597f8cc3181caf4d4b7
Closes-Bug: #1333399