Delete InstanceSystemMetadata on instance deletion

Thanks to no-db-compute only pre-delete instance data is used in
notifications. So now we can go back to deleting InstanceSystemMetadata
when an instance is deleted.

Fixes bug 1153827

Change-Id: Ic66b998cde2a15a24f302f08c34753a8b57da73d
Sync oslo-incubator print statement changes

Just changes openstack.common to use the new print statements.

This is in preparation for another sync coming shortly for the
scheduler library.

Change-Id: I17a86ef87f3253d6bb756cbd40a3ff5df9be23ff
Merge "Delete InstanceSystemMetadata on instance deletion"
Merge "Sync oslo-incubator print statement changes"