Amend PIDFile path in systemd service
Amend PIDFile path in systemd service

The PID paths in the Nginx compile options and systemd service file don't match. I hadn't noticed this before today, as it turned out I was using a different nginx.service file (presumably from a previous install), so the one included in the script never got installed.
Without this change, I was unable to stop the service using `sudo systemctl stop nginx` (no errors reported, but the processes were left running).
MatthewVance/nginx-build