crypto/x509: fix go pointer to cgo
crypto/x509: fix go pointer to cgo

https://travis-ci.org/shanemhansen/gossl/jobs/253728568#L359

Signed-off-by: Vincent Batts <d01a4772f0cffd3f005a7d7f01c59cd104c7a5fe@hashbangbash.com>

shanemhansen/gossl,shanemhansen/gossl