lib/init.sh: fix parsing kernel cmdline

[YukariChiba]

The kernel parses parameters from the kernel command line up to "--"; if it doesn't recognize a parameter and it doesn't contain a '.', the parameter gets passed to init: parameters with '=' go into init's environment, others are passed as command line arguments to init. Everything after "--" is passed as an argument to init.

Args after -- should be passed to the init process as init_args.