Merge pull request tronprotocol#2017 from tronprotocol/backup_dup1

checkDupWitness add syncFinish check logic

Author: olenheim

src/main/java/org/tron/core/services/WitnessService.java

@@ -338,6 +338,10 @@ public void checkDupWitness(BlockCapsule block) {
       return;
     }
 
+    if (needSyncCheck) {
+      return;
+    }
+
     if (System.currentTimeMillis() - block.getTimeStamp() > ChainConstant.BLOCK_PRODUCED_INTERVAL) {
       return;
     }