lib, zebra: extend use of sockunion2ip macro

  * lib/sockunion.c,
  * zebra/zebra_rib.c: replace ->sin.sin_addr.s_addr with sockunion2ip

Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
[reworded commit message]
Signed-off-by: David Lamparter <equinox@diac24.net>
diff --git a/lib/sockunion.c b/lib/sockunion.c
index 4c2837b..37dc3f9 100644
--- a/lib/sockunion.c
+++ b/lib/sockunion.c
@@ -370,7 +370,7 @@
       su->sin.sin_len = size;
 #endif /* HAVE_STRUCT_SOCKADDR_IN_SIN_LEN */
       if (su_addr == NULL)
-	su->sin.sin_addr.s_addr = htonl (INADDR_ANY);
+	sockunion2ip (su) = htonl (INADDR_ANY);
     }
 #ifdef HAVE_IPV6
   else if (su->sa.sa_family == AF_INET6)
@@ -727,9 +727,9 @@
 
   if (su1->sa.sa_family == AF_INET)
     {
-      if (ntohl (su1->sin.sin_addr.s_addr) == ntohl (su2->sin.sin_addr.s_addr))
+      if (ntohl (sockunion2ip (su1)) == ntohl (sockunion2ip (su2)))
 	return 0;
-      if (ntohl (su1->sin.sin_addr.s_addr) > ntohl (su2->sin.sin_addr.s_addr))
+      if (ntohl (sockunion2ip (su1)) > ntohl (sockunion2ip (su2)))
 	return 1;
       else
 	return -1;