pxeboot com0 no more

[matthew sporleder <msporleder%gmail.com@localhost>]

I recall reading that pxeboot_ia32_com0.bin was changed because
installboot could be used for setting serial options, but I'm a little
confused on how to get setup initially with a binary distribution.  If
I use pxeboot_ia32.bin from HEAD's base.tgz, it doesn't work over
com0, my ability to run 'installboot' on it from a non-netbsd system
is pretty limited, and so I'm stuck.

Just a bit of chicken-and-egg I ran into last night.

Luckily, 3.0's base.tgz distro includes pxeboot_ia32_com0.bin.

_Matt