sthttpd: Fix service unit file

Update PID file path from /var/run to /run to avoid systemd warning:
    PIDFile= references a path below legacy directory /var/run/,
    updating /var/run/thttpd.pid → /run/thttpd.pid; please update
    the unit file accordingly.

Cc: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Alexis Cellier <alexis.cellier@smile.fr>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-webserver/recipes-httpd/sthttpd/sthttpd/thttpd.service

@@ -3,8 +3,8 @@ Description=Tiny/Turbo/Throttling Web Server
 
 [Service]
 Type=forking
-ExecStart=/usr/sbin/thttpd -C @@CONFFILE -c cgi-bin/* -i /var/run/thttpd.pid
-PIDFile=/var/run/thttpd.pid
+ExecStart=/usr/sbin/thttpd -C @@CONFFILE -c cgi-bin/* -i /run/thttpd.pid
+PIDFile=/run/thttpd.pid
 
 [Install]
 WantedBy=multi-user.target