Expose ProjectConfigSchemaUpdate status

When a project config gets updated, it is useful to expose
its update status so that external processors (e.g. Schema migrators)
can do wise counting and statistics based on that.

Change-Id: I9d47da14d4eb852f4e9a8112a54702700b6e2434

gerrit-server/src/main/java/com/google/gerrit/server/schema/ProjectConfigSchemaUpdate.java

@@ -103,4 +103,8 @@ public class ProjectConfigSchemaUpdate extends VersionedMetaData {
       throw new OrmException(e);
     }
   }
+
+  public boolean isUpdated() {
+    return updated;
+  }
 }