Clean up a couple of %Q issues in "Has Parents" task queries

Summary: Stragglers from the great "%Q" migration.

Test Plan: Ran a query for tasks with parent tasks.

Reviewers: amckinley

Reviewed By: amckinley

Differential Revision: https://secure.phabricator.com/D20183

src/applications/maniphest/query/ManiphestTaskQuery.php

@@ -618,9 +618,9 @@ final class ManiphestTaskQuery extends PhabricatorCursorPagedPolicyAwareQuery {
     $joins = array();
     if ($this->hasOpenParents !== null) {
       if ($this->hasOpenParents) {
-        $join_type = 'JOIN';
+        $join_type = qsprintf($conn, 'JOIN');
       } else {
-        $join_type = 'LEFT JOIN';
+        $join_type = qsprintf($conn, 'LEFT JOIN');
       }
 
       $joins[] = qsprintf(