Remove string attribute from views

issue2350

view/split_start_form.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
 this repository contains the full copyright notices and license terms. -->
-<form string="Split Move" col="6">
+<form col="6">
     <label name="count"/>
     <field name="count"/>
     <label name="quantity"/>