Field maxcommrate is not mutated

[anton-trunov]

Commit b710edc

Is there a missing transition that should set the maxcommrate field?
If this is not the case then it should perhaps be made a constant or a contract immutable parameter.

[bb111189]

Yes, I think it can be made constant. The purpose of maxcommrate is to ensure that operators do not set commission rate is that more than 100%, resulting in potential unexpected behavior