ActionJson: Add workInProgress to ChangeInfo copy method

In I322ff79c7 ChangeInfo was extended with workInProgress attribute, but
ActionJson#copy method was missed to be extended.

Change-Id: I929a6777e8be8ace72c737a494f0371d98152ba7

gerrit-server/src/main/java/com/google/gerrit/server/change/ActionJson.java

@@ -139,6 +139,7 @@ public class ActionJson {
     copy.stars = changeInfo.stars;
     copy.submitted = changeInfo.submitted;
     copy.submitter = changeInfo.submitter;
+    copy.workInProgress = changeInfo.workInProgress;
     copy.id = changeInfo.id;
     return copy;
   }