tap: Trace received (outbound) ICMP packets in debug mode, too

This only worked for ICMPv6: ICMP packets have no TCP-style header,
so they are handled as a special case before packet sequences are
formed, and the call to tap_packet_debug() was missing.

Fixes: bb70811183 ("treewide: Packet abstraction with mandatory boundary checks")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

tap.c

@@ -463,6 +463,8 @@ resume:
 			if (c->no_icmp)
 				continue;
 
+			tap_packet_debug(iph, NULL, NULL, 0, NULL, 1);
+
 			packet_add(pkt, l4_len, l4h);
 			icmp_tap_handler(c, AF_INET, &iph->daddr, pkt, now);
 			continue;