fix checking whether file was already fixed

Thank you for creating the hook!

Note, There was no need for punch-fix-utf8 on Linux, but on Mac a different 'rain dance' was needed, so I had to change it slightly to make fix work on Mac: https://github.com/avalez/yoga-azbuka/commit/959cec78a834e84cce57fe8fd0de34d36757601a, not sure it's worth for merging into original repository.