* lib/rubygems/package/old.rb:  Disallow installation of old-format
	  gems when a security policy is active.
	* test/rubygems/test_gem_package_old.rb:  Test for above.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39142 b2dd03c8-39d4-4d8f-98ff-823fe69b080e