[DRE-maint] Bug#841820: pdfwalker does not start

[val uk]

Package: origami-pdf
Version: 1.2.7-3
 
When launching pdfwalker, I get the following error:
 
 /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': superclass mismatch for class Date (TypeError)
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/date.rb:4:in `<top (required)>'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/psych/deprecated.rb:2:in `<top (required)>'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/psych.rb:19:in `<top (required)>'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/yaml.rb:6:in `<top (required)>'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/share/origami/gui/config.rb:26:in `<top (required)>'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/share/origami/gui/walker.rb:51:in `<top (required)>'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/bin/pdfwalker:4:in `<main>'

This seems related to bug  #806133. I found out that moving the line "require 'yaml'" from /usr/share/origami/gui/config.rb to /usr/share/origami/gui/walker.rb (just after line "include Gtk") fixes the problem. Being not familiar with ruby, though, I'm not sure this doesn't break something else.