Enforce sizelimit in permission-find, post_callback returns truncated
We actually perform two searches in permission-find. The first looks
for matches within the permission object itself. The second looks at
matches in the underlying aci.
We need to break out in two places. The first is if we find enough
matches in the permission itself. The second when we are appending
matches from acis.
The post_callback() definition needed to be modified to return
the truncated value so a plugin author can modify that value.