Fix ref leak in mempool updates
Fix ref leak in mempool updates

shsmith/electrumx,shsmith/electrumx,thelazier/electrumx,thelazier/electrumx,Crowndev/electrumx,Crowndev/electrumx,Groestlcoin/electrumx-grs,bauerj/electrumx,bauerj/electrumx,erasmospunk/electrumx,erasmospunk/electrumx,Groestlcoin/electrumx-grs