Import in latest mtree from NetBSD to fix a bug in parsing group files
that jmg fixed upstream.

MFC after:	1 week
Sponsored by:	DARPA, AFRL


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273796 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f