generate-linux-fonts.rb: drop sha256 stanza for no_check value

Drops `sha256` stanza for no_check value instead of passing it through which probably causes Homebrew#54

cmd/generate-linux-fonts.rb

@@ -90,9 +90,7 @@ def format_stanza(stanza, value, args = {})
  return "" if value.nil?
 
  if stanza == :sha256 && value == "no_check"
- <<-EOS
- #{stanza} :#{value}
- EOS
+ "" # Drop `sha256` stanza in formula altogether
  elsif [:url, :head].include?(stanza)
  <<-EOS
  #{stanza} #{format_url(value, args)}