weston-launch: Don't exit on SIGTERM

Instead, forward signal to weston and wait for weston to clean up nicely.
Weston relies on weston-launch being around to shut down correctly,
so don't exit until we get the SIGCHLD from weston.  This make
killall weston-launch work properly.

https://bugs.freedesktop.org/show_bug.cgi?id=62910
1 file changed