iproute2: add a missing return statement

Since do_help() has to return an int to fit in the table of commands,
it should actually return an int. This patch lets it do so.
Signed-off-by: Kees van Reeuwijk <reeuwijk@few.vu.nl>

ip/ip.c

@@ -57,6 +57,7 @@ static void usage(void)
 static int do_help(int argc, char **argv)
 {
 	usage();
+        return 0;
 }
 
 static const struct cmd {