sserver: add new field `session_id` to common event `miner_connect` and `miner_dead`.
sserver: add new field `session_id` to common event `miner_connect` and `miner_dead`.

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