Ruby

ChangeLog: doc accidentally squashed commit in r51036

Oops :x

• hash.c (rb_hash_fetch_m): remove unnecessary volatile since r41597
  (env_reject_bang): trade volatile for GC guard
  (env_select): ditto
  (env_select_bang): ditto
  (env_keep_if): ditto
  (rb_env_clear): ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51038 b2dd03c8-39d4-4d8f-98ff-823fe69b080e