[FIX] website_event_track: urltype has been removed from kanban

Before Odoo 9.0, `type="url"` leaded
to the use of `do_action_url` in `kanban.js`, which
basically redirected to the link url.

This action no longer exists in Odoo 9.0, besides, this
is not really useful, you are redirected
anyway when using a `<a href="..."/>`.

opw-668215

addons/website_event_track/views/event_backend.xml

@@ -20,7 +20,7 @@
                                         <span class="fa fa-bars fa-lg"/>
                                     </a>
                                     <ul class="dropdown-menu" role="menu" aria-labelledby="dLabel">
-                                        <li><a t-att-href="record.website_url.value" type="url">View Track</a></li>
+                                        <li><a t-att-href="record.website_url.value">View Track</a></li>
                                         <t t-if="widget.editable"><li><a type="edit">Edit Track</a></li></t>
                                         <t t-if="widget.deletable"><li><a type="delete">Delete</a></li></t>
                                         <li><ul class="oe_kanban_colorpicker" data-field="color"/></li>