Fix two errors from the error logs

Summary: Found these in the `secure` error logs: one bad call, one bad column.

Test Plan: Searched for empty string. Double-checked method name.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D16948

src/applications/search/fulltextstorage/PhabricatorMySQLFulltextStorageEngine.php

@@ -238,7 +238,7 @@ final class PhabricatorMySQLFulltextStorageEngine
     } else {
       $select[] = qsprintf(
         $conn,
-        'document.dateCreated AS fieldScore');
+        'document.documentCreated AS fieldScore');
     }
 
     $exclude = $query->getParameter('exclude');

src/infrastructure/cluster/PhabricatorDatabaseRef.php

@@ -635,7 +635,7 @@ final class PhabricatorDatabaseRef
     $application_replicas = array();
     $default_replicas = array();
     foreach ($replicas as $replica) {
-      $master = $replica->getMaster();
+      $master = $replica->getMasterRef();
 
       if ($master->isApplicationHost($application)) {
         $application_replicas[] = $replica;