validation: Remove redundant request sync from ProcessNewBlock().
validation: Remove redundant request sync from ProcessNewBlock().

ProcessNewBlock is called by ProcessMessage (NetMsgType::BLOCK command) which is doing the exact same check: if the node does not have the previous block, request sync up to it.

Darknet-Crypto/Darknet,Darknet-Crypto/Darknet,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,Darknet-Crypto/Darknet,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,Darknet-Crypto/Darknet,Darknet-Crypto/Darknet,Darknet-Crypto/Darknet,PIVX-Project/PIVX