Clean up MergeException

Change-Id: I961e5a11cb9f75fbc4905da5c6f956ec968cde2d

gerrit-server/src/main/java/com/google/gerrit/server/git/MergeException.java

diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeException.java b/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeException.java
index 54cd329..d3ebb95 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeException.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeException.java
@@ -18,11 +18,15 @@
 public class MergeException extends Exception {
   private static final long serialVersionUID = 1L;
 
-  public MergeException(final String msg) {
-    super(msg, null);
+  public MergeException(String msg) {
+    super(msg);
   }
 
-  public MergeException(final String msg, final Throwable why) {
+  public MergeException(Throwable why) {
+    super(why);
+  }
+
+  public MergeException(String msg, Throwable why) {
     super(msg, why);
   }
 }