Fix method visibility for PhabricatorPolicyAwareQuery subclasses

Summary: Ref T6822.

Test Plan:
`grep` for the following:

  - `->willFilterPage(`
  - `->loadPage(`
  - `->didFilterPage(`
  - `->getReversePaging(`
  - `->didFilterPage(`
  - `->willExecute(`
  - `->nextPage(`

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: hach-que, Korvin, epriestley

Maniphest Tasks: T6822

Differential Revision: https://secure.phabricator.com/D11367

src/applications/repository/query/PhabricatorRepositoryPushEventQuery.php

@@ -49,7 +49,7 @@ final class PhabricatorRepositoryPushEventQuery
     return $table->loadAllFromArray($data);
   }
 
-  public function willFilterPage(array $events) {
+  protected function willFilterPage(array $events) {
     $repository_phids = mpull($events, 'getRepositoryPHID');
     $repositories = id(new PhabricatorRepositoryQuery())
       ->setViewer($this->getViewer())
@@ -69,7 +69,7 @@ final class PhabricatorRepositoryPushEventQuery
     return $events;
   }
 
-  public function didFilterPage(array $events) {
+  protected function didFilterPage(array $events) {
     $phids = mpull($events, 'getPHID');
 
     if ($this->needLogs) {