[openfirmware] patch to fail more gracefuly when nvsetenv doesn't work

[Robert Millan]

Could someone test this on an OpenFirmware machine for which nvsetenv works?

The idea is that for those machines in which nvsetenv isn't usable, at least
user gets to know what command to type.

-- 
Robert Millan

My spam trap is address@hidden  Note: this address is only intended
for spam harvesters.  Writing to it will get you added to my black list.

nvsetenv.diff
Description: Text Data