Use new STACK_OF helpers.

Bug: 132
Change-Id: Ib9bc3ce5f60d0c5bf7922b3d3ccfcd15ef4972a1
Reviewed-on: https://boringssl-review.googlesource.com/18466
Reviewed-by: David Benjamin <davidben@google.com>

ssl/internal.h

diff --git a/ssl/internal.h b/ssl/internal.h
index cb39a93..c8a96a4 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -2032,7 +2032,7 @@
 CERT *ssl_cert_dup(CERT *cert);
 void ssl_cert_clear_certs(CERT *c);
 void ssl_cert_free(CERT *c);
-int ssl_set_cert(CERT *cert, CRYPTO_BUFFER *buffer);
+int ssl_set_cert(CERT *cert, UniquePtr<CRYPTO_BUFFER> buffer);
 int ssl_is_key_type_supported(int key_type);
 /* ssl_compare_public_and_private_key returns one if |pubkey| is the public
  * counterpart to |privkey|. Otherwise it returns zero and pushes a helpful