readWitness seems not include secret input discard function as previous version

[mdj33]

io.ReadWitness(fInputPath, r1csInput)

previous:
func (assignments Assignments) DiscardSecrets() Assignments {
toReturn := NewAssignment()
for k, v := range assignments {
if v.IsPublic {
toReturn[k] = v
}
}
return toReturn
}

[gbotrel]

Thanks for reporting, indeed the issue was when trying to assign public values only to a witness, fixed in #38