BitcoinLink: Fix pre-Feb20 "version" checksum handling
BitcoinLink: Fix pre-Feb20 "version" checksum handling

ahmedbodi/SHA-Eloipool-MMCFE-,uingei/eloipool,uingei/eloi,svasva/eloipool,wizkid057/eloipool,thrasher-/eloipool,imsaguy/eloipool,cinnamoncoin/eloipool-1,thrasher-/eloipool,thrasher-/eloipool,jameshilliard/4tar-eloipool,pointgaming/point-gaming-btc