Do not check against textual IP addresses in DNSname SAN field
Currently the gnutls verification functions will allow matching an IP address which is stored in the DNSName field of the certificate. This was to allow some misconfigured sites to work. That behavior is even documented.
Suphannee Sivakorn has identified that from OpenSSL, GnuTLS, MbedTLS, MatrixSSL, JSSE, CPython SSL, only GnuTLS, MbedTLS and MatrixSSL have this behavior. As such, given that openssl doesn't support that behavior we should remove that compatibility code.