Correct a bug introduced in 1.26: M_PKTHDR is set in the 'flags'
argument, not the 'type' argument. As a result of the buf, the
MAC label on some packet header mbufs might not be set in mbufs
allocated using m_getcl(), resulting in a page fault.

Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs