edit_item_alter submit: page not found if multilingual is activated

Hello,

I'm using menuimage on a multilingual website,
After editing a menu item I'm redirected to a 404 page only if the editing page URL is prefixed with the current page language.
Example :

'admin/structure/menu/item/%nid/edit'
The redirection will work but the URL will have an extra slash : mysite.com//admin/structure/menu/item/%nid/edit

'fr/admin/structure/menu/item/%nid/edit'
This one will fail and the landing page will have this URL : mysite.com/fr//admin/structure/menu/item/%nid/edit

This issue is caused by the redirect option defined in the hook_form_edit_item_submit() :
$form_state['redirect'] = ("/admin/structure/menu/item/" . $mlid . "/edit");

Deleting the first slash solve the issue
$form_state['redirect'] = ("admin/structure/menu/item/" . $mlid . "/edit");