nginx (S50nginx): Fix stop, reload, restart. Add force-reload.

nginx (S50nginx): Fix stop, reload, restart. Add force-reload.

Fix package/nginx/S50nginx:

* On stop, use start-stop-daemon -R 1 to wait for the nginx processes
  to actually stop.  This fixes a race condition with restart, where
  nginx fails to restart because start is called too early
  w.r.t. stop.  (This only works with Debian's start-stop-daemon,
  however BusyBox's start-stop-daemon does not fail when given -R; it
  just ignores the argument silently).

* Implement reload with an actual reload instead of a restart.

* Add force-reload.

Signed-off-by: Thomas Claveirole <thomas.claveirole@green-communications.fr>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>