INSTALL-BTCPool.md: add libhiredis as the dependency.
INSTALL-BTCPool.md: add libhiredis as the dependency.

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