Don't change ownership of PID_FOLDER

Update the launch script so that it no longer changes ownership of the
PID_FOLDER.

Commit b24e736cfe had changed the chown
line from:
	chown "$run_user" "$PID_FOLDER/${identity}"
to:
	chown "$run_user" "$PID_FOLDER"

This meant that it was possible for the launch script to change
ownership of `/var/run` and prevent later processes from writing to
the folder.

Since PID_FOLDER is created before the chown statement, and that
the `checkPermissions` function runs to ensure that the PID file can
be written, it appears that the chown is not even required.

Fixes gh-6532

spring-boot-tools/spring-boot-loader-tools/src/main/resources/org/springframework/boot/loader/tools/launch.script

@@ -143,7 +143,6 @@ do_start() {
   mkdir "$PID_FOLDER" &> /dev/null
   if [[ -n "$run_user" ]]; then
     checkPermissions || return $?
-    chown "$run_user" "$PID_FOLDER"
     chown "$run_user" "$pid_file"
     chown "$run_user" "$log_file"
     if [ $USE_START_STOP_DAEMON = true ] && type start-stop-daemon > /dev/null 2>&1; then