Revert "Add PIDFile for uWSGI."

This reverts commit 30f1e63a6c.

config/uwsgi.ini

@@ -3,7 +3,6 @@ socket = 127.0.0.1:9001
 wsgi-file = app.py
 callable = app
 virtualenv = venv
-safe-pidfile = /run/calefaction/pid
 
 processes = 1
 threads = 4