Fix committing the notes from the export command.

Since the reviewnotes logic was moved from Gerrit core into the reviewnotes
plugin the export command was broken. The notes were created but not committed.

Change-Id: I3e4d01f661b64c5d528f562aa2352dc43615e4f3
diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
index 4cdf04a..7232e26 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
@@ -155,12 +155,13 @@
         monitor = NullProgressMonitor.INSTANCE;
       }
 
-      NoteMap notes = NoteMap.newEmptyMap();
       for (Change c : changes) {
         monitor.update(1);
         PatchSet ps = reviewDb.patchSets().get(c.currentPatchSetId());
         ObjectId commitId = ObjectId.fromString(ps.getRevision().get());
-        notes.set(commitId, createNoteContent(rw.parseCommit(commitId)));
+        RevCommit commit = rw.parseCommit(commitId);
+        getNotes().set(commitId, createNoteContent(commit));
+        getMessage().append("* ").append(commit.getShortMessage()).append("\n");
       }
     } finally {
       rw.release();