Issue upgrade guidance to rebuild indexes for the Ferret engine

Summary:
Ref T12819. This is shipping, so issue upgrade guidance to instruct installs to rebuild the index.

Also generate a new `quickstart.sql` since we haven't regenerated in a bit and there's been a large amount of table churn fairly recently.

Test Plan: Ran `bin/storage upgrade`, saw guidance notification in UI.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12819

Differential Revision: https://secure.phabricator.com/D18594

resources/sql/autopatches/20170912.ferret.01.activity.php

@@ -0,0 +1,19 @@
+<?php
+
+// Advise installs to perform a reindex in order to rebuild the Ferret engine
+// indexes.
+
+// If the install is completely empty with no user accounts, don't require
+// a rebuild. In particular, this happens when rebuilding the quickstart file.
+$users = id(new PhabricatorUser())->loadAllWhere('1 = 1 LIMIT 1');
+if (!$users) {
+  return;
+}
+
+try {
+  id(new PhabricatorConfigManualActivity())
+    ->setActivityType(PhabricatorConfigManualActivity::TYPE_REINDEX)
+    ->save();
+} catch (AphrontDuplicateKeyQueryException $ex) {
+  // If we've already noted that this activity is required, just move on.
+}