Don't try to create the Aphlict log directory if it already exists

Summary: Ref T6944. This was not quite implemented correctly in D11387.

Test Plan: Saw no more exceptions about being unable to create `/var/log`.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: maxhodak, Korvin, epriestley

Maniphest Tasks: T6944

Differential Revision: https://secure.phabricator.com/D11397

src/applications/aphlict/management/PhabricatorAphlictManagementWorkflow.php

@@ -39,7 +39,9 @@ abstract class PhabricatorAphlictManagementWorkflow
 
     try {
       $dir = dirname($path);
+      if (!Filesystem::pathExists($dir)) {
         Filesystem::createDirectory($dir, 0755, true);
+      }
     } catch (FilesystemException $ex) {
       throw new Exception(
         pht(