xhtml_style: fill request.form during Base_renderForm

Base_renderForm was using request.set - which only sets in request.other,
and this causes Base_renderForm to behaves differently from Base_redirect
with forms looking explicitly in request.form, like for example listbox
does before calling the list method.

bt5/erp5_ui_test/PathTemplateItem/portal_tests/page_templates_zuite/testDialogActions.zpt

@@ -50,6 +50,16 @@
   <td>"Update" action is done with "A value from the user".</td>
   <td></td>
 </tr>
+<tr>
+  <td>assertValue</td>
+  <td>//input[@name="field_your_string_field"]</td>
+  <td>A value from the user</td>
+</tr>
+<tr>
+  <td>assertTextPresent</td>
+  <td>A value pushed by update action</td>
+  <td></td>
+</tr>
 <tr>
   <td>clickAndWait</td>
   <td>Base_callDialogMethod:method</td>

bt5/erp5_ui_test/SkinTemplateItem/portal_skins/erp5_ui_test/Foo_updateAction.py

 """Call the Foo_viewDummyDialog"""
-kw.update(context.REQUEST.form)
-return context.ERP5Site_redirect("%s/Foo_viewDummyDialog" % context.absolute_url(),
-        keep_items={'portal_status_message': '"Update" action is done with "%s".' % string_field}, **kw)
+return context.Base_renderForm(
+  'Foo_viewDummyDialog',
+  message='"Update" action is done with "%s".' % string_field,
+  keep_items={
+    'key_posted_during_on_update': 'A value pushed by update action'
+  }
+)

bt5/erp5_ui_test/SkinTemplateItem/portal_skins/erp5_ui_test/Foo_viewDummyDialog.xml

@@ -76,6 +76,7 @@
                     <value>
                       <list>
                         <string>your_string_field</string>
+                        <string>your_inspect_request</string>
                       </list>
                     </value>
                 </item>

product/ERP5/bootstrap/erp5_xhtml_style/SkinTemplateItem/portal_skins/erp5_xhtml_style/Base_renderForm.py

@@ -22,5 +22,6 @@ if REQUEST is None:
 
 for key, value in keep_items.items():
   REQUEST.set(key, value)
+  REQUEST.form[key] = value
 
 return getattr(context, form_id)()