Fix segfault in debug build

ext/mysqlnd/mysqlnd.c

@@ -571,6 +571,10 @@ PHPAPI MYSQLND *mysqlnd_connect(MYSQLND *conn,
 											    NULL /*ctx*/, &errstr, &errcode);
 	DBG_INF_FMT("stream=%p", conn->net.stream);
 
+	if (errstr || !conn->net.stream) {
+		goto err;
+	}
+
 	if (hashed_details) {
 		/*
 		  If persistent, the streams register it in EG(persistent_list).
@@ -597,10 +601,6 @@ PHPAPI MYSQLND *mysqlnd_connect(MYSQLND *conn,
 		mnd_efree(hashed_details);
 	}
 
-	if (errstr || !conn->net.stream) {
-		goto err;
-	}
-
 	if (conn->options.timeout_read)
 	{
 		tv.tv_sec = conn->options.timeout_read;