Revert "HDFS-7857. Improve authentication failure WARN message to avoid user confusion. Contributed by Yongjun Zhang."

This reverts commit d799fbe1ccf8752c44f087e34b5f400591d3b5bd.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java

@@ -1324,15 +1324,10 @@ public abstract class Server {
           saslResponse = processSaslMessage(saslMessage);
         } catch (IOException e) {
           rpcMetrics.incrAuthenticationFailures();
-          if (LOG.isDebugEnabled()) {
-            LOG.debug(StringUtils.stringifyException(e));
-          }
           // attempting user could be null
-          IOException tce = (IOException) getTrueCause(e);
           AUDITLOG.warn(AUTH_FAILED_FOR + this.toString() + ":"
-              + attemptingUser + " (" + e.getLocalizedMessage()
-              + ") with true cause: (" + tce.getLocalizedMessage() + ")");
-          throw tce;
+              + attemptingUser + " (" + e.getLocalizedMessage() + ")");
+          throw (IOException) getTrueCause(e);
         }
         
         if (saslServer != null && saslServer.isComplete()) {