Create the Aphlict PID directory

Summary: Fixes T6944. Create the Aphlict PID directory if it does not exist. See also D11387.

Test Plan: Started Aphlict... saw PID directory created.

Reviewers: anton.vladimirov, epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Maniphest Tasks: T6944

Differential Revision: https://secure.phabricator.com/D11906