In ssl_check_public_cert(), also take dNSNames in the subjectAltName

extension into account when checking the cert against the configured
ServerName. PR 32652, PR 47051.

Replace SSL_X509_getCN() by SSL_X509_getIDs(), which returns an array
of a cert's DNS-IDs and CN-IDs (terms as coined by RFC 6125).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1176752 13f79535-47bb-0310-9956-ffa450edef68