Add --foreground option for nscd

Add --foreground option for nscd

For a better integration of nscd with systemd, we should run nscd not as
daemon but in the foreground. A new --foreground option should be added.

2012-05-09  Alexandre Oliva  <aoliva@redhat.com>
	    Andreas Jaeger  <aj@suse.de>

        * nscd/nscd.c (go_background): Replaced with...
        (run_mode): ... this.
	(RUN_FOREGROUND, RUN_DAEMONIZE, RUN_DEBUG): Add.
        (options): Add -F --foreground.
        (main): Implement it.
        (parse_opt): Parse it.