[refactoring] simplify signature of _finish function
[refactoring] simplify signature of _finish function

This is a follow-up to commit e05257035ca9dfa53c59ec5b7aa451dc061b452d.

Change-Id: Ia05f533c3c14d926b3c524175260cfcf0bb09e1e

openstack/ironic-inspector,openstack/ironic-inspector