fix(net):if num is bigger than head num, get blockid from khaosdb

Author: 317787106

framework/src/main/java/org/tron/core/net/service/sync/SyncService.java

@@ -210,7 +210,9 @@ private LinkedList<BlockId> getBlockChainSummary(PeerConnection peer) throws P2p
 
   private BlockId getBlockIdByNum(long num) throws P2pException {
     BlockId head = tronNetDelegate.getHeadBlockId();
-    if (num == head.getNum()) {
+    if (num > head.getNum()) {
+      return tronNetDelegate.getKhaosDbHeadBlockId();
+    } else if (num == head.getNum()) {
       return head;
     }
     return tronNetDelegate.getBlockIdByNum(num);