fontbakery: TRACEBACK Failure to generate ghmarkdown for Unna

Tried to Generate a markdown report for the following PR, https://github.com/Omnibus-Type/Unna/pull/6

CLI input:

fontbakery check-googlefonts ~/Documents/googlefonts/manual_font_cleaning/Unna/fonts/ttf/*.ttf --ghmarkdown ~/Desktop/Unna.md

Traceback:

Traceback (most recent call last):
  File "/Users/marc/Documents/googlefonts/fontbakery/venv_dev/bin/fontbakery", line 9, in <module>
    load_entry_point('fontbakery==0.5.1.dev28+g39c4540c', 'console_scripts', 'fontbakery')()
  File "/Users/marc/Documents/googlefonts/fontbakery/Lib/fontbakery/cli.py", line 22, in main
    "fontbakery.commands." + subcommand_module, run_name='__main__')
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/runpy.py", line 208, in run_module
    return _run_code(code, {}, init_globals, run_name, mod_spec)
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/Users/marc/Documents/googlefonts/fontbakery/Lib/fontbakery/commands/check_googlefonts.py", line 28, in <module>
    sys.exit(main())
  File "/Users/marc/Documents/googlefonts/fontbakery/Lib/fontbakery/commands/check_specification.py", line 287, in main
    args.ghmarkdown.write(mdr.get_markdown())
  File "/Users/marc/Documents/googlefonts/fontbakery/Lib/fontbakery/reporters/ghmarkdown.py", line 87, in get_markdown
    "".join(map(self.check_md, family_checks)) + "<br>")
  File "/Users/marc/Documents/googlefonts/fontbakery/Lib/fontbakery/reporters/ghmarkdown.py", line 44, in check_md
    checkid = check["key"][1].split(":")[1].split(">")[0]
IndexError: list index out of range

Fontbakery version 0.5.1.dev28+g39c4540c