Properly create xhpast database

Summary:
It isn't deleted by `storage destroy`.

This should be a no-op on current storage because we execute `CREATE DATABASE IF NOT EXISTS`.

Test Plan:
  $ bin/storage destroy --dryrun

Reviewers: nh, epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3659

resources/sql/patches/xhprof.sql

@@ -1,4 +1,3 @@
-CREATE DATABASE {$NAMESPACE}_xhprof;
 CREATE TABLE {$NAMESPACE}_xhprof.xhprof_sample (
   `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
   `filePHID` VARCHAR(64) NOT NULL COLLATE utf8_bin,

src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php

@@ -167,6 +167,10 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type'    => 'db',
         'name'    => 'ponder',
       ),
+      'db.xhpast' => array(
+        'type'    => 'db',
+        'name'    => 'xhpast',
+      ),
       '0000.legacy.sql' => array(
         'type'    => 'sql',
         'name'    => $this->getPatchPath('0000.legacy.sql'),