ossl_asn1.c: fix undefined behavior
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45701 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
ossl_asn1.c: fix undefined behavior
other than Symbol is an undefined behavior. fix up r31699.
[ruby-core:62142] [Bug #9771]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45701 b2dd03c8-39d4-4d8f-98ff-823fe69b080e