Add "Manual Activities", to tell administrators to rebuild the search index

Summary:
Ref T11922. After updating to HEAD of `master`, you need to manually rebuild the index. We don't do this during `bin/storage upgrade` because it can take a very long time (`secure.phabricator.com` took roughly an hour) and can happen while Phabricator is running.

However, if we don't warn users about this they'll just get a broken index unless they go read the changelog (or file an issue, then we tell them to go read the changelog).

This adds a very simple table for notes to administrators so we can write a "you need to go rebuild the index" note, then adds one.

Administrators clear the note by completing the activity and running `bin/config done reindex`. This isn't automatic because there are various strategies you can use to approach the issue, which I'll discuss in greater detail in the linked documentation.

Also, fix an issue where `bin/storage upgrade --apply <patch>` could try to re-mark an already-applied patch as applied.

Test Plan:
  - Ran storage ugrades.
  - Got instructions to rebuild search index.
  - Cleared instructions with `bin/config done reindex`.

Reviewers: chad

Reviewed By: chad

Subscribers: avivey

Maniphest Tasks: T11922

Differential Revision: https://secure.phabricator.com/D16965

resources/sql/autopatches/20161130.search.01.manual.sql

@@ -0,0 +1,6 @@
+CREATE TABLE {$NAMESPACE}_config.config_manualactivity (
+  id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  activityType VARCHAR(64) NOT NULL COLLATE {$COLLATE_TEXT},
+  parameters LONGTEXT NOT NULL COLLATE {$COLLATE_TEXT},
+  UNIQUE KEY `key_type` (activityType)
+) ENGINE=InnoDB, COLLATE {$COLLATE_TEXT};

resources/sql/autopatches/20161130.search.02.rebuild.php

@@ -0,0 +1,26 @@
+<?php
+
+$search_engine = PhabricatorFulltextStorageEngine::loadEngine();
+$use_mysql = ($search_engine instanceof PhabricatorMySQLFulltextStorageEngine);
+
+if ($use_mysql) {
+  $field = new PhabricatorSearchDocumentField();
+  $conn = $field->establishConnection('r');
+
+  // We're only going to require this if the index isn't empty: if you're on a
+  // fresh install, you don't have to do anything.
+  $any_documents = queryfx_one(
+    $conn,
+    'SELECT * FROM %T LIMIT 1',
+    $field->getTableName());
+
+  if ($any_documents) {
+    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.
+    }
+  }
+}