Add buttons on custom stock move list

This allows to cancel stock move from the purchase form.

issue3945
review26371002

view/move_list_shipment.xml

@@ -9,5 +9,7 @@ this repository contains the full copyright notices and license terms. -->
     <field name="uom"/>
     <field name="state"/>
     <field name="purchase_exception_state"/>
+    <button name="cancel" string="Cancel"/>
+    <button name="draft" string="Reset to Draft"/>
     <field name="unit_digits" tree_invisible="1"/>
 </tree>