Scapy upgrade to 2.4.0.rc5

- many of the patches fd.io applies in test/patches/2.3.3 are now upstreamed in 2.4
- 2.4 adds support for IGMPv3 which is my main motivation for the upgrade

Change-Id: If2c0a524e3cba320b4a5d8cd07817c6ea2bf0c5a
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/test/test_ipsec_ah.py b/test/test_ipsec_ah.py
index 6e73241..e1259de 100644
--- a/test/test_ipsec_ah.py
+++ b/test/test_ipsec_ah.py
@@ -303,9 +303,8 @@
                 self.pg1, send_pkts, self.pg0, count=count)
             # ESP TUN VPP encryption verification
             for recv_pkt in recv_pkts:
-                recv_pkt[IP] = recv_pkt[IP] / IP(recv_pkt[AH].icv[12:])
-                recv_pkt[AH].icv = recv_pkt[AH].icv[:12]
                 decrypt_pkt = self.local_tun_sa.decrypt(recv_pkt[IP])
+                decrypt_pkt = IP(decrypt_pkt[Raw].load)
                 self.assert_equal(decrypt_pkt.src, self.remote_pg1_lb_addr)
                 self.assert_equal(decrypt_pkt.dst, self.remote_pg0_lb_addr)
         finally: