CCBC-550: Fix pillowfight --set-ratio with values higher than 50

Change-Id: I91504ebd8d81a57d845b40a9375bb94a7e45b7d2
Reviewed-on: http://review.couchbase.org/43389
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>