MB-7497: Remove min_data_age and queue_age_cap

Change-Id: I0436294b0c28fde6f205a991c6160cac65003e2d
Reviewed-on: http://review.couchbase.org/23753
Reviewed-by: Jin Lim <jin@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>