Description of problem:
puppet 3.7.1 which is currently in rawhide is not supported on Ruby 2.2

I got the following error while trying to run it:

/usr/share/ruby/vendor_ruby/puppet/defaults.rb:465: warning: duplicated key at line 466 ignored: :queue_type
/usr/share/ruby/vendor_ruby/puppet/vendor/safe_yaml/lib/safe_yaml/syck_node_monkeypatch.rb:42:in `<top (required)>': uninitialized constant Syck (NameError)
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/ruby/vendor_ruby/puppet/vendor/safe_yaml/lib/safe_yaml.rb:197:in `<module:YAML>'
	from /usr/share/ruby/vendor_ruby/puppet/vendor/safe_yaml/lib/safe_yaml.rb:132:in `<top (required)>'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/ruby/vendor_ruby/puppet/vendor/require_vendored.rb:4:in `<top (required)>'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/ruby/vendor_ruby/puppet/vendor.rb:40:in `require_libs'
	from /usr/share/ruby/vendor_ruby/puppet/vendor.rb:53:in `load_vendored'
	from /usr/share/ruby/vendor_ruby/puppet.rb:172:in `<module:Puppet>'
	from /usr/share/ruby/vendor_ruby/puppet.rb:29:in `<top (required)>'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/ruby/vendor_ruby/puppet/util/command_line.rb:12:in `<top (required)>'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /usr/bin/puppet:7:in `<main>'

Here is the related upstream bz https://tickets.puppetlabs.com/browse/PUP-3796

Patch can be found here: https://github.com/Yelp/puppet/commit/fd6aba67d1b2fe41eca7292d2f8602f63a56b4b8

Tested and works.