Convert reference counts in crypto/

This change converts the reference counts in crypto/ to use
|CRYPTO_refcount_t|. The reference counts in |X509_PKEY| and |X509_INFO|
were never actually used and so were dropped.

Change-Id: I75d572cdac1f8c1083c482e29c9519282d7fd16c
Reviewed-on: https://boringssl-review.googlesource.com/4772
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_cert.c

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 770912b..6cb3785 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -128,6 +128,7 @@
 
 #include "../crypto/dh/internal.h"
 #include "../crypto/directory.h"
+#include "../crypto/internal.h"
 #include "internal.h"
 
 
@@ -269,12 +270,12 @@
   ret->cert_cb_arg = cert->cert_cb_arg;
 
   if (cert->verify_store) {
-    CRYPTO_add(&cert->verify_store->references, 1, CRYPTO_LOCK_X509_STORE);
+    CRYPTO_refcount_inc(&cert->verify_store->references);
     ret->verify_store = cert->verify_store;
   }
 
   if (cert->chain_store) {
-    CRYPTO_add(&cert->chain_store->references, 1, CRYPTO_LOCK_X509_STORE);
+    CRYPTO_refcount_inc(&cert->chain_store->references);
     ret->chain_store = cert->chain_store;
   }
 
@@ -977,7 +978,7 @@
   *pstore = store;
 
   if (ref && store) {
-    CRYPTO_add(&store->references, 1, CRYPTO_LOCK_X509_STORE);
+    CRYPTO_refcount_inc(&store->references);
   }
   return 1;
 }