hostapd: several fixes for init script

* restart: The stop may delay a few seconds according to different wireless
  devices, on debian/ubuntu, the init script directly sleep 8 seconds
  to wait the stop complete, here we add a delay function (sleep in a loop)
  to ensure the stop is completed before start.
* add status command.
* add --oknodo for stop so it will not break restart if there is no
  running process.

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>