[link-detect] Improve BSD support.

[link-detect] Improve BSD support.
2008-01-11 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* lib/zebra.h: Revert previous change, no need to include
	  <net/if_media.h> here.
	* zebra/ioctl.c: If HAVE_BSD_LINK_DETECT is defined, include
	  <net/if_media.h>
	  (if_get_flags) Remove debug messages about BSD link state.
	* zebra/kernel_socket.c: (bsd_linkdetect_translate) If link state
	  is unknown, we should set the IFF_RUNNING flag.