lib: replace string concatenation with template

PR-URL: #16923
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

lib/_http_client.js

@@ -116,7 +116,7 @@ function ClientRequest(options, cb) {
 
   var path;
   if (options.path) {
-    path = '' + options.path;
+    path = String(options.path);
     var invalidPath;
     if (path.length <= 39) { // Determined experimentally in V8 5.4
       invalidPath = isInvalidPath(path);