* sys/net/if_gif.c: fix uninitialized variable, which can lead to   kernel panic.
* sys/net/if_gif.c: fix uninitialized variable, which can lead to
  kernel panic.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame