social/mail_activity_crm/views/crm_lead_menu.xml

<?xml version="1.0"?>
<odoo>
<data>
    <!-- hide -->
    <record id="crm.crm_lead_menu_activities" model="ir.ui.menu">
        <field name="groups_id" eval="[(6, 0, [ref('base.group_no_one')])]"/>
        <field name="name">Next Activities (obsolete)</field>
    </record>

</data>
</odoo>