fix bug: If miner send authorize info without password, the stratum server will crash
fix bug: If miner send authorize info without password, the stratum server will crash

btccom/btcpool,btccom/btcpool,btccom/btcpool,btccom/btcpool,btccom/btcpool,btccom/btcpool,btccom/btcpool,btccom/btcpool