Bug in teacher/assisant.rs

[naokikob]

I found a bug in the following part of the code src/teacher/assistant.rs: 262-269

            log! { @3
                "trying to break\n{}",
                data.constraints[cstr].to_string_info(self.instance.preds()).unwrap()
            }
            // Can happen because of simplifications when propagating.
            if cstr > data.constraints.len() {
                break;
            }

The first four lines should be swapped with the rest. Otherwise a runtime exception would occur on the 3rd line
when cstr > data.constraints.len().