Fix for failure of periodic instance cleanup

The periodic task to identify and (optionally) delete instances which
are running on the host but marked as deleted in the nova database currently fails
if the option to delete is selected.

This failure is because the instance data returned from the query in
nova.compute.manager:_get_instances_on_driver does not include the system metadata
expected by nova.compute.flavors:extract_instance_type.

This change alters _get_instances_on_driver so the calling function can specify
columns_to_join which is used in the call to instance_get_all_by_filters (leaving
this set to None, rather than [] as it is currently, joins the default columns which
includes the required system metadata).

bug: 1190206

Change-Id: I44aecebdb4d0e20e52fdd59b46a022483cdd19d5
Merge "Fix for failure of periodic instance cleanup"