backport r32987 from trunk.
ext/openssl/ossl_pkey.c: corrected docs, OpenSSL::PKey::DH does not support #sign/verify.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@32989 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
backport r32987 from trunk.
ext/openssl/ossl_pkey.c: corrected docs, OpenSSL::PKey::DH does
not support #sign/verify.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@32989 b2dd03c8-39d4-4d8f-98ff-823fe69b080e