Update lib/_http_agent.js

Author: aduh95

lib/_http_agent.js

@@ -478,7 +478,7 @@ Agent.prototype.keepSocketAlive = function keepSocketAlive(socket) {
     const keepAliveHint = socket._httpMessage.res.headers['keep-alive'];
 
     if (keepAliveHint) {
-      const hint = keepAliveHint.exec(/^timeout=(\d+)/)?.[1];
+      const hint = /^timeout=(\d+)/.exec(keepAliveHint)?.[1];
 
       if (hint) {
         const serverHintTimeout = NumberParseInt(hint) * 1000;