gae_proxy: cert_util: add subjectAltName extension
gae_proxy: cert_util: add subjectAltName extension

Both Firefox and Chrome now require "subjectAltName" to exist instead
of just "commonName". Otherwise they report SSL_ERROR_BAD_CERT_DOMAIN
and net::ERR_CERT_COMMON_NAME_INVALID, respectively.

This fixes #5044, fixes #5093, fixes #5106, fixes #5110, and
fixes #5116.
xyuanmu/XX-Net,zlsun/XX-Net,qqzwc/XX-Net,xyuanmu/XX-Net,zlsun/XX-Net,xyuanmu/XX-Net,zlsun/XX-Net,qqzwc/XX-Net,qqzwc/XX-Net,zlsun/XX-Net,xyuanmu/XX-Net,qqzwc/XX-Net,zlsun/XX-Net,xyuanmu/XX-Net,qqzwc/XX-Net