package/nginx: use /run for PIDFile

Fixes:

systemd[1]: /usr/lib/systemd/system/nginx.service:7: PIDFile= references
a path below legacy directory /var/run/, updating /var/run/nginx.pid →
/run/nginx.pid; please update the unit file accordingly.

Signed-off-by: Michael Nosthoff <buildroot@heine.tech>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/nginx/nginx.service

@@ -4,7 +4,7 @@ After=syslog.target network.target
 
 [Service]
 Type=forking
-PIDFile=/var/run/nginx.pid
+PIDFile=/run/nginx.pid
 ExecStartPre=/usr/bin/mkdir -p /var/log/nginx /var/tmp/nginx
 ExecStartPre=/usr/sbin/nginx -t -q -g 'pid /var/run/nginx.pid; daemon on; master_process on;'
 ExecStart=/usr/sbin/nginx -g 'pid /var/run/nginx.pid; daemon on; master_process on;'