ggsn.c: Print version of unhandled ip packet

Change-Id: I7e226a12b074c96c572f90e3aaf62716d0cd47c5
diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c
index 0beaef7..763a2c5 100644
--- a/ggsn/ggsn.c
+++ b/ggsn/ggsn.c
@@ -653,7 +653,7 @@
 		dst.v6 = ip6h->ip6_dst;
 		pool = apn->v6.pool;
 	} else {
-		LOGP(DTUN, LOGL_NOTICE, "non-IPv packet received from tun\n");
+		LOGP(DTUN, LOGL_NOTICE, "non-IPv%u packet received from tun\n", iph->version);
 		return -1;
 	}