Clone options in attach-link to prevent requestOptions changes from persisting

lib/proto/attach-form.js

@@ -6,10 +6,11 @@ var clone = require("../clone")
 var attrClick = "data-pjax-click-state"
 
 var formAction = function(el, event) {
-  // Since we'll be modifying request options, clone the existing options
-  // so these changes don't persist
+  // Since loadUrl modifies options and we may add our own modifications below,
+  // clone it so the changes don't persist
   var options = clone(this.options);
 
+  // Initialize requestOptions
   options.requestOptions = {
     requestUrl: el.getAttribute("action") || window.location.href,
     requestMethod: el.getAttribute("method") || "GET",