Fix typo in GRE tunnels (i_key vs. o_key).

From: <herbert@gondor.apana.org.au>

If a dotted quad ikey is specified for GRE tunnels, it gets set as the
okey instead.  This patch fixes it.

See Debian bug #200714 - http://bugs.debian.org/200714

Patch from Debian iproute package.

--- iproute/ip/iptunnel.c.orig  2003-07-10 11:47:06.000000000 +1000
+++ iproute/ip/iptunnel.c       2003-07-10 11:47:11.000000000 +1000
@@ -221,7 +221,7 @@
			NEXT_ARG();
			p->i_flags |= GRE_KEY;
			if (strchr(*argv, '.'))
-				p->o_key = get_addr32(*argv);
+				p->i_key = get_addr32(*argv);
			else {
				if (get_unsigned(&uval, *argv, 0)<0) {
					fprintf(stderr, "invalid value of \"ikey\"\n");