config/private: wrap init.el in file-directory-p check

modules/config/private/init.el

@@ -7,6 +7,7 @@
   "The directory that serves as the root of your external private config for
 Doom Emacs.")
 
+(when (file-directory-p +private-config-path)
   ;; Ensure `doom//reload-autoloads', `doom//byte-compile' and
   ;; `doom-initialize-packages' will treat `+private-config-path' as the root of
   ;; this module.
@@ -15,4 +16,4 @@ Doom Emacs.")
 
   ;;
   (load (expand-file-name "init.el" +private-config-path)
-      'noerror 'nomessage)
+        :noerror :nomessage))