Use isChangeRef instead of isRef

Change-Id: I042c389ef83773dd3eb9184d4930950548950c08
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushResultProcessing.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushResultProcessing.java
index a053b2e..c63d346 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushResultProcessing.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushResultProcessing.java
@@ -190,7 +190,7 @@
     }
 
     private void postEvent(String project, String ref, RefEvent event) {
-      if (PatchSet.isRef(ref)) {
+      if (PatchSet.isChangeRef(ref)) {
         try (ReviewDb db = schema.open()) {
           Change change = retrieveChange(ref, db);
           if (change != null) {