> gem2rpm --fetch redcarpet
/usr/lib64/ruby/2.1.0/open-uri.rb:223:in `open_loop': redirection forbidden:
http://rubygems.org/api/v1/gems/redcarpet.json ->
https://rubygems.org/api/v1/gems/redcarpet.json (RuntimeError)
        from /usr/lib64/ruby/2.1.0/open-uri.rb:149:in `open_uri'
        from /usr/lib64/ruby/2.1.0/open-uri.rb:704:in `open'
        from /usr/lib64/ruby/2.1.0/open-uri.rb:34:in `open'
        from /usr/lib64/ruby/gems/2.1.0/gems/gem2rpm-0.10.1/bin/gem2rpm:114:in
`<top (required)>'
        from /usr/bin/gem2rpm:23:in `load'  
        from /usr/bin/gem2rpm:23:in `<main>'


to fix, it needs a s/http/https/ in
/usr/lib64/ruby/gems/2.1.0/gems/gem2rpm-0.10.1/bin/gem2rpm:114

but maybe we just want to completely update this version,
because it produces spec-files with ruby-macros >= 3
and does not understand many yaml parts