Fix ironic inspector rule creation idempotency

Ironic inspector rules are registered both with the seed and (if using)
overcloud ironic inspector services. These tasks often show up as
changed even when no configuration changes have been made that would
affect the rules.

This is caused by inspector returning default values for fields that may
be omitted in the requested rule. This change fixes the issue by
including those defaults in the comparison.

Change-Id: Ia24e328d4531201d76a65b6385e4463bb1f3c5c6
Story: 2007399
Task: 38997