precheck: remove obsolete comment It was added in 65d4e47d7f26, and applied to the code that was executed if the if block right above this line (i.e. one that returns the result of core precheck) did not run (in other words, it applied to the imaginary "else" clause). Now we have a different check in the if block above, and the compatibility comment placed is above it. So let's remove this obsolete comment that no longer applies.