Broken constructor pattern from recent commit

Created by: gswalden

This commit https://github.com/OptimalBits/bull/commit/1f2d1bcba4993b1b38dc101b553e988523749c43 broke the alternative Queue constructor (from the README) Queue(queueName, redisConnectionString, [redisOpts]), as adding the redisOpts argument will cause arguments.length === 3, and which causes the later call to redis.clientClient() to break with TypeError: Unknown type of connection in createClient().

I'm simply editing my code to get around this issue, but thought you should know!