* lib/rubygems.rb, lib/rubygems/*, test/rubygems/*: Update rubygems-2.6.1.

Please see entries of 2.6.0 and 2.6.1 on
  https://github.com/rubygems/rubygems/blob/master/History.txt
  [fix GH-1270] Patch by @segiddins

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53992 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rubygems/commands/open_command.rb

@@ -15,6 +15,10 @@ class Gem::Commands::OpenCommand < Gem::Command
                "Opens gem sources in EDITOR") do |editor, options|
       options[:editor] = editor || get_env_editor
     end
+    add_option('-v', '--version VERSION', String,
+               "Opens specific gem version") do |version|
+      options[:version]  = version
+    end
   end
 
   def arguments # :nodoc: