Fix typo in invocation of print_usage
Fix typo in invocation of print_usage

jts/nanopolish,mateidavid/nanopolish,mateidavid/nanopolish,mateidavid/nanopolish,jts/nanopolish,jts/nanopolish,mateidavid/nanopolish,jts/nanopolish,mateidavid/nanopolish,jts/nanopolish