Convert reference counts in ssl/

Convert reference counts in ssl/ to use |CRYPTO_refcount_t|.

Change-Id: I5d60f641b0c89b1ddfe38bfbd9d7285c60377f4c
Reviewed-on: https://boringssl-review.googlesource.com/4773
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_sess.c

diff --git a/ssl/ssl_sess.c b/ssl/ssl_sess.c
index 3eb428f..b358b5e 100644
--- a/ssl/ssl_sess.c
+++ b/ssl/ssl_sess.c
@@ -607,14 +607,14 @@
 
 SSL_SESSION *SSL_SESSION_up_ref(SSL_SESSION *session) {
   if (session) {
-    CRYPTO_add(&session->references, 1, CRYPTO_LOCK_SSL_SESSION);
+    CRYPTO_refcount_inc(&session->references);
   }
   return session;
 }
 
 void SSL_SESSION_free(SSL_SESSION *session) {
   if (session == NULL ||
-      CRYPTO_add(&session->references, -1, CRYPTO_LOCK_SSL_SESSION) > 0) {
+      !CRYPTO_refcount_dec_and_test_zero(&session->references)) {
     return;
   }