Hardcoded font path failure

[ACodingfreak]

OS: Centos7

./rfc2kindle.py -i rfc7379.txt

Unable to find font: /usr/share/cups/fonts/Courier
Convert IETF RFC TXT file to HTML for kindlegen
-h --help This message
-i --input input file
Traceback (most recent call last):
File "./rfc2kindle.py", line 219, in
main()
File "./rfc2kindle.py", line 104, in main
usage()
File "./rfc2kindle.py", line 22, in usage
print "-f --font font file to use for monospace images (default:%s)" % defaultfont
NameError: global name 'defaultfont' is not defined

[marauderlabs]

Same on Debian.
cat /etc/debian_version
8.4

After fixing NameError: global name 'defaultfont' is not defined

[eproxus]

This seems to be a bug on line 22: https://github.com/cobblau/RFC2Kindle/blob/master/rfc2kindle.py#L22

If you change it to default_font it works (given that you use the -f argument on platforms where the default font doesn't exist).