hash.c: revert

* hash.c (rb_hash_reject): revert to deprecated behavior, with
  warnings, due to compatibility for HashWithDifferentAccess.
  [ruby-core:59154] [Bug #9223]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44263 b2dd03c8-39d4-4d8f-98ff-823fe69b080e