Only implemented for the i386; behaviour for other ports is
unchanged. For the i386, make this function remove some extraneous
files in /, and frob rc.conf to have rc_configured=YES. The defaults
are reasonable, and it saves the user having to set TERM and mount
filesystems by hand in order to be able to edit /etc/rc.conf
(XXX not very clean, but it's a workaround to be more user-friendly
for 1.3.2)
Also adapt a few messages slightly so they apply to both situations.