Improve error message when publishing an already published change edit

Change-Id: I7ec3503ea96fc9a7f88009db248c99642dc9ba80
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditUtil.java b/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditUtil.java
index 0cfdeed..6509ecc 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditUtil.java
@@ -231,7 +231,7 @@
                         IOException.class.getName(),
                         edit.getRefName(),
                         RefUpdate.Result.LOCK_FAILURE.name()))) {
-          throw new ResourceConflictException("edit ref was updated");
+          throw new ResourceConflictException("edit is already published");
         }
       }