hash.c: ensure NUL-terminated for ENV
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55345 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
hash.c: ensure NUL-terminated for ENV
[ruby-dev:49655] [Bug #12475]
NUL-terminated content.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55345 b2dd03c8-39d4-4d8f-98ff-823fe69b080e