Pop one from tx_counts for each block we back up.
Pop one from tx_counts for each block we back up.

Fixes #40

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