fix typo: s/@ca_cert/@cacert/

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40048 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Suppress warnings

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40049 b2dd03c8-39d4-4d8f-98ff-823fe69b080e