MB-11306 Correctly compare map scores with star replication.

Previously we incorrectly also compared maps themselves.

Change-Id: If95d1c1dbb187841b940353deef023673fd51429
Reviewed-on: http://review.couchbase.org/37848
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>