make compaction logging more informative
make compaction logging more informative

Change-Id: Ifc1982e02f9a8f4f9f0e6180d6345d48a5dc70a9
Reviewed-on: http://review.couchbase.org/51490
Tested-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>
Reviewed-by: Poonam D <6855f09986fe28ed7e8cdd9d60db878d898703d5@couchbase.com>

nimishzynga/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,ceejatec/ns_server,mschoch/ns_server,nimishzynga/ns_server,ceejatec/ns_server,nimishzynga/ns_server,mschoch/ns_server,mschoch/ns_server,membase/ns_server,mschoch/ns_server,ceejatec/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,nimishzynga/ns_server,mschoch/ns_server,mschoch/ns_server,ceejatec/ns_server,membase/ns_server