Fix unassigned instance in OTM1 audit migrations

model_hasattr was not returning a value for the success case where getattr doesn't raise.
Fix audit migrations

Update the object_id to the newly created OTM2 ids for all audits.

For 'create' audits, which are really 'pk' changes, update the 'pk' value to the correct OTM2 id.
Add mgmt command for basic otm1 migration checks
Merge pull request #1193 from steventlamb/bug/fix_audit_migrator_pks

Bug/fix audit migrator pks