The fallback license should require at least attribution.

In case Proprietary Relicensing happens, copyleft is effectively wiped out.
What remains is a fallback license of sorts, which should at least require attribution I think...
I wonder if this is enough, I can't figure out well enough what is the effective result,
if it is enough for a license in its own right and what would happen when all the
fun questions would be asked (compatibility...)

Signed-off-by: Engel Nyst <engel.nyst@gmail.com>