* ext/openssl/ossl_x509attr.c: change OSSL_X509ATTR_IS_SINGLE and
  OSSL_X509ATTR_SET_SINGLE macros to use ->value.set rather than
  ->set to fix compile failure

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41527 b2dd03c8-39d4-4d8f-98ff-823fe69b080e