Add SIGPWR support to lxc_init

This patch adds SIGPWR support to lxc_init.
This helps to properly shutdown lxc_init based containers.

Signed-off-by: Nikolay Martynov <mar.kolya@gmail.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Sysvinit script fixes

Signed-off-by: Stefano Ansaloni <ansalonistefano@gmail.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>