erp5_web_renderjs_ui: always clear the file input when rendering the field

Prevent sending the binary each time.
Follow file input behaviour

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_filefield_js.js

@@ -27,31 +27,23 @@
       return this.changeState(state_dict);
     })
 
-    .onStateChange(function (modification_dict) {
+    .onStateChange(function () {
       var element = this.element,
         gadget = this,
-        url,
-        result;
-      if (modification_dict.hasOwnProperty('editable')) {
-        if (gadget.state.editable) {
-          url = 'gadget_html5_input.html';
-        } else {
-          url = 'gadget_html5_element.html';
-        }
-        result = this.declareGadget(url, {scope: 'sub'})
-          .push(function (input) {
-            // Clear first to DOM, append after to reduce flickering/manip
-            while (element.firstChild) {
-              element.removeChild(element.firstChild);
-            }
-            element.appendChild(input.element);
-            return input;
-          });
+        url;
+      if (gadget.state.editable) {
+        url = 'gadget_html5_input.html';
       } else {
-        result = this.getDeclaredGadget('sub');
+        url = 'gadget_html5_element.html';
       }
-      return result
+      return this.declareGadget(url, {scope: 'sub'})
         .push(function (input) {
+          // Clear first to DOM, append after to reduce flickering/manip
+          while (element.firstChild) {
+            element.removeChild(element.firstChild);
+          }
+          element.appendChild(input.element);
+
           return input.render(gadget.state);
         });
     })