Ruby » Ruby master

merge revision(s) 41175: [Backport #8502]

    * class.c (include_modules_at): invalidate method cache if included
      module contains constants

    * test/ruby/test_module.rb: add test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@41192 b2dd03c8-39d4-4d8f-98ff-823fe69b080e