I added this in upstream to prevent people from accidentally flashing
roms without a payload resulting in a no boot situation, but in
libreboot lbmk handles the payload and thus this warning always comes
up. This has caused confusion and concern so just patch it out.

python 3 is default now, in all the distros

specifically calling "python3" often doesn't work anymore

python2 is obsolete

let python2 die

courtesy of Angel Pons from the coreboot project

this uses the following patch set from gerrit, as yet
unmerged (in coreboot master) on this date:

    https://review.coreboot.org/c/coreboot/+/64198/5

logic for downloading mrc blobs has been deleted from
lbmk, as this is now completely obsolete (for haswell
boards)

if other platforms are added later that need mrc.bin,
then logic will be re-added again for that