Merge pull request #944 from tronprotocol/hotfix/preValidateTransaction_exception

fix exception handle

Author: olenheim

src/main/java/org/tron/core/db/Manager.java

@@ -1272,8 +1272,13 @@ private static class ValidateSignTask implements Callable<Boolean> {
 
     @Override
     public Boolean call() throws ValidateSignatureException {
-      trx.validateSignature();
-      countDownLatch.countDown();
+      try {
+        trx.validateSignature();
+      } catch (ValidateSignatureException e) {
+        throw e;
+      } finally {
+        countDownLatch.countDown();
+      }
       return true;
     }
   }