HBASE-7436 Improve stack trace info dumped by ForeignExceptionSnare#rethrowException

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/hbase-7290@1445800 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/errorhandling/ForeignExceptionDispatcher.java

@@ -87,7 +87,9 @@ public class ForeignExceptionDispatcher implements ForeignExceptionListener, For
   @Override
   public void rethrowException() throws ForeignException {
     if (exception != null) {
-      throw exception;
+      // This gets the stack where this is caused, (instead of where it was deserialized).
+      // This which is much more useful for debugging
+      throw new ForeignException(exception.getSource(), exception.getCause());
     }
   }