bug#26791: Attempt to apply a string as a procedure during Hydra evaluation

[Danny Milosavljevic]

Hi,

I think it always works (also without compilation) when I move the 
boot-parameters record definition up in gnu/system.scm (so it comes before its 
clients).

It's still reconfiguring now but it looks good.

If it works out, I'll post it here for review...