slight tuning of /etc/mk situation when making release.
- Make the bootstrap /etc/mk be populated from the newly checked out source
- Don't chmod 755 all of /etc
- For the 'real' /etc/mk installing, let the /etc/mk ownership and permission
come from the mtree file, delete the contents of /etc/mk, then copy the .mk
files over and set reasonable permissions and ownership. (So that the .mk
get updated from the real usr/src/ copies, and no other junk if anything,
after the bootstrap phase, whatever happened there.)