'Get the filename of the nfo file from the \'location\' in the entry.
Returns
str
The file name of the \'nfo\' file, or None it there is no \'nfo\' file.'

def get_nfo_filename(self, entry):

    location = entry.get(u'location')
    nfo_full_filename = (os.path.splitext(location)[0] + self.nfo_file_extension)
    if os.path.isfile(nfo_full_filename):
        return nfo_full_filename
