blockchain: Reject old block vers for pow vote.

This updates the latest block version for the upcoming hard fork vote
for DCP0011 and DCP0012 in order to reject old block versions once a
super majority of the network has upgraded.

internal/blockchain/validate.go

@@ -1011,7 +1011,7 @@ func isDCP0005Violation(network wire.CurrencyNet, header *wire.BlockHeader, bloc
 func (b *BlockChain) isOldBlockVersionByMajority(header *wire.BlockHeader, blockHash *chainhash.Hash, prevNode *blockNode) bool {
 	// Note that the latest block version for all networks other than the main
 	// network is one higher.
-	latestBlockVersion := int32(9)
+	latestBlockVersion := int32(10)
 	if b.chainParams.Net != wire.MainNet {
 		latestBlockVersion++
 	}