bitfield runs into NPE if executed inside a transaction

[mp911de]

Caused by: java.lang.NullPointerException
    at com.lambdaworks.redis.output.ArrayOutput.set(ArrayOutput.java:38)
    at com.lambdaworks.redis.output.MultiOutput.set(MultiOutput.java:49)
    at com.lambdaworks.redis.protocol.RedisStateMachine.safeSet(RedisStateMachine.java:367)
    at com.lambdaworks.redis.protocol.RedisStateMachine.decode(RedisStateMachine.java:147)
    at com.lambdaworks.redis.protocol.CommandHandler.decode(CommandHandler.java:303)

[mp911de]

Fixed.