Pull up following revision(s) (requested by uwe in ticket #1534):
sys/net/if_mpls.c: 1.31-1.33 via patch
sys/netmpls/mpls_ttl.c: 1.9 via patch
Style, and fix several bugs:
- ip4_check(), mpls_unlabel_inet() and mpls_unlabel_inet6() perform
  pullups, so we need to pass the updated pointers back
- in mpls_lse() the route is not always freed
Looks a little better now.
--
Kick MPLS packets earlier.
--
Several changes:
* In mpls_unlabel_inet, copy the label locally. It's not incorrect to
  keep a pointer on the mbuf, but it's bug-friendly.
* In mpls_label_inetX, fix the length check. Meanwhile add an XXX: we
  just want to make sure that m_copydata won't fail, but if we were
  guaranteed that m has M_PKTHDR set, we could simply check the length
  against m->m_pkthdr.len.

(snj)