merge revision(s) 43587: [Backport #8623]

	* tool/rbinstall.rb (Gem::Specification#collect): make stable
	  Gem::Specification.files in default .gemspecs the different order of
	  "files" in .gemspec files makes them different therefore possibly
	  conflicting in multilib scenario.  patch by vo.x (Vit Ondruch) at
	  [ruby-core:57544] [Bug #8623].


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@44567 b2dd03c8-39d4-4d8f-98ff-823fe69b080e