DragonFlyBSD

The attached patch (also located at
http://www.rumko.net/dragonfly/0001-tmpfs-Correct-checking-of-VWRITE.patch)
fixes an incorrect check in tmpfs_access and enables to chroot to schg dirs
once again.

This problem is especially noticable on diskless boots where /var/empty is
inside a tmpfs mount (and as a consequence, you can't ssh into that machine).
--
Please do not CC me, since I already receive everything from these MLs.

Regards,
Rumko