crypto: fix memory leak in LoadPKCS12

`sk_X509_pop_free` should be used instead of `sk_X509_free` to free all
items in queue too, not just the queue itself.

PR-URL: https://github.com/nodejs/node/pull/5109
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Shigeki Ohtsu <ohtsu@iij.ad.jp>

src/node_crypto.cc

@@ -1001,7 +1001,7 @@ void SecureContext::LoadPKCS12(const FunctionCallbackInfo<Value>& args) {
   if (cert != nullptr)
     X509_free(cert);
   if (extra_certs != nullptr)
-    sk_X509_free(extra_certs);
+    sk_X509_pop_free(extra_certs, X509_free);
 
   PKCS12_free(p12);
   BIO_free_all(in);