Minor remarks on the setup-storage manpage

[Michael Goetze]

Hi FAI devs,

I was just reading setup-storage(8) and noticed a few things. First of 
all, do we still need the "Migration from setup_harddisks" section in 
FAI 4.0? I think setup_harddisks has been deprecated for long enough now 
that it should not be an issue anymore for 4.0. Comments?

Secondly, I think mt should be credited for much more than just the 
"initial version" in the Authors section. ;)

Regards,
Michael