src: fix memory leak introduced in 34febfb

Fix leaking the BIO in the error path.  Introduced in commit 34febfb
("crypto: fix handling of root_cert_store").

PR-URL: nodejs#9604
Refs: nodejs#9409
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Rod Vagg <rod@vagg.org>

src/node_crypto.cc

@@ -770,9 +770,8 @@ void SecureContext::AddCRL(const FunctionCallbackInfo<Value>& args) {
       PEM_read_bio_X509_CRL(bio, nullptr, CryptoPemCallback, nullptr);
 
   if (crl == nullptr) {
-    return env->ThrowError("Failed to parse CRL");
     BIO_free_all(bio);
-    return;
+    return env->ThrowError("Failed to parse CRL");
   }
 
   X509_STORE* cert_store = SSL_CTX_get_cert_store(sc->ctx_);