Fix fallout from r243019, which broke parsing of shortened network

prefixes.

Reported and tested by:	delphij

sbin/route/route.c

@@ -1032,6 +1032,13 @@ inet_makenetandmask(u_long net, struct sockaddr_in *sin, u_long bits)
 
 	rtm_addrs |= RTA_NETMASK;
 
+	/*
+	 * MSB of net should be meaningful. 0/0 is exception.
+	 */
+	if (net > 0)
+		while ((net & 0xff000000) == 0)
+			net <<= 8;
+
 	/*
 	 * If no /xx was specified we must calculate the
 	 * CIDR address.