* lib/rubygems: Update to RubyGems 2.2.0.preview.1

This brings several new features to RubyGems summarized here:

  https://github.com/rubygems/rubygems/blob/v2.2.0.preview.1/History.txt

* test/rubygems:  ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42967 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rubygems/commands/uninstall_command.rb

@@ -15,7 +15,7 @@ class Gem::Commands::UninstallCommand < Gem::Command
   def initialize
     super 'uninstall', 'Uninstall gems from the local repository',
           :version => Gem::Requirement.default, :user_install => true,
-          :install_dir => Gem.dir, :check_dev => false
+          :check_dev => false
 
     add_option('-a', '--[no-]all',
       'Uninstall all matching versions'
@@ -84,7 +84,6 @@ class Gem::Commands::UninstallCommand < Gem::Command
 
   def defaults_str # :nodoc:
     "--version '#{Gem::Requirement.default}' --no-force " +
-    "--install-dir #{Gem.dir}\n" +
     "--user-install"
   end
 
@@ -104,8 +103,7 @@ that is a dependency of an existing gem.  You can use the
 
   def execute
     if options[:all] and not options[:args].empty? then
-      alert_error 'Gem names and --all may not be used together'
-      terminate_interaction 1
+      uninstall_specific
     elsif options[:all] then
       uninstall_all
     else