DisplayManager: turn on display when boot manager finishes the boot again

When the compositor goes down the boot manager will now cycle through startup state again
to correctly launch all things again and we have to turn the display on at this time to
make sure the compositor is back in sync with us.

Signed-off-by: Simon Busch <morphis@gravedo.de>
Merge pull request #9 from webOS-ports/morphis/boot-display-on

DisplayManager: turn on display when boot manager finishes the boot agai...