MB-9096 remove new_style suffixes and prefixes from janitor_agent

Change-Id: Ia95b9730d3e7bd426565c525f197fe15a740d6de
Reviewed-on: http://review.couchbase.org/29399
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>