Add more information to compactor's log message

Include the maximum number of log files to apply per btree for each
retry phase.

Change-Id: I5189021e87818d817ce205081fdbddf2044662ce
Reviewed-on: http://review.couchbase.org/33989
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>