OCSP stapling: staple now extracted via SSL_get_certificate().
OCSP stapling: staple now extracted via SSL_get_certificate().

This makes it possible to properly return OCSP staple with multiple
certificates configured.

Note that it only works properly in OpenSSL 1.0.1d+, 1.0.0k, 0.9.8y+.
In older versions SSL_get_certificate() fails to return correct certificate
when the certificate status callback is called.

hy0kl/nginx,hy0kl/nginx,hy0kl/nginx