cmake: add optional dependency (libsasl2) of librdkafka
cmake: add optional dependency (libsasl2) of librdkafka

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