fix ui update frequency during sync phase.
fix ui update frequency during sync phase.

repos-bitcoin/bitc,dxtr/bitc,dxtr/bitc,Methimpact/bitc,repos-bitcoin/bitc,dxtr/bitc,bit-c/bitc,bit-c/bitc,repos-bitcoin/bitc,Methimpact/bitc,Methimpact/bitc,jma127/bitc-rpc,jma127/bitc-rpc,bit-c/bitc,jma127/bitc-rpc