* vm_insnhelper.c (vm_call_method): should check ci->me->flag of
  a refining method in case the method is private.
  [ruby-core:60111] [Bug #9452]

* vm_method.c (make_method_entry_refined): set me->flag of a refined
  method entry to NOEX_PUBLIC in case the original method is private
  and it is refined as a public method.  The original flag is stored
  in me->def->body.orig_me, so it's OK to make a refined method
  entry public.  [ruby-core:60111] [Bug #9452]

* test/ruby/test_refinement.rb: related tests.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44931 b2dd03c8-39d4-4d8f-98ff-823fe69b080e