mpls broken again

[Martin Husemann <martin%duskware.de@localhost>]

Some recent changes (no idea which) broke the MPLS regression tests:

PING 10.0.4.1 (10.0.4.1): 64 data bytes
72 bytes from 10.0.4.1: icmp_seq=2 ttl=255 time=12.450469 ms

----10.0.4.1 PING Statistics----
3 packets transmitted, 1 packets received, 66.7% packet loss
round-trip min/avg/max/stddev = 12.450469/12.450469/12.450469/0.000000 ms

Haven't we seen this before? Crash when trying to answer the first packet
or something?

Martin