Read "Database Status" page connection information from cluster config if present

Summary:
Fixes T11043. This page was still reading the old information directly instead of going through the cluster-aware stuff.

Have it ask the cluster-aware stuff for information instead.

Test Plan:
  - Nuked MySQL on localhost.
  - Configured cluster hosts.
  - Loaded "Database Status" page -- worked after patch.
  - Grepped for any remaining `mysql.configuration-provider` stragglers, came up empty.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11043

Differential Revision: https://secure.phabricator.com/D15982

Author: epriestley

src/applications/config/controller/PhabricatorConfigDatabaseController.php

@@ -4,16 +4,14 @@ abstract class PhabricatorConfigDatabaseController
   extends PhabricatorConfigController {
 
   protected function buildSchemaQuery() {
-    $conf = PhabricatorEnv::newObjectFromConfig(
-      'mysql.configuration-provider',
-      array($dao = null, 'w'));
+    $ref = PhabricatorDatabaseRef::getMasterDatabaseRef();
 
     $api = id(new PhabricatorStorageManagementAPI())
-      ->setUser($conf->getUser())
-      ->setHost($conf->getHost())
-      ->setPort($conf->getPort())
+      ->setUser($ref->getUser())
+      ->setHost($ref->getHost())
+      ->setPort($ref->getPort())
       ->setNamespace(PhabricatorLiskDAO::getDefaultStorageNamespace())
-      ->setPassword($conf->getPassword());
+      ->setPassword($ref->getPass());
 
     $query = id(new PhabricatorConfigSchemaQuery())
       ->setAPI($api);