[REF] purchase_requisition: requisition type editable only in draft s…

…tate

Purchase requisitions have two different type available : purchase tender
and blanket order. As the behaviours between these two types are very different,
the type is now locked once the requisition is no more in draft state.

addons/purchase_requisition/views/purchase_requisition_views.xml

@@ -151,7 +151,7 @@
                     <group>
                         <field name="is_quantity_copy" invisible='1'/>
                         <field name="user_id" attrs="{'readonly': [('state','not in',('draft','in_progress','open'))]}"/>
-                        <field name="type_id" attrs="{'readonly': [('state','not in',('draft','in_progress','open'))]}" widget="selection"/>
+                        <field name="type_id" attrs="{'readonly': [('state','!=','draft')]}" widget="selection"/>
                         <field name="vendor_id" context="{'search_default_supplier':1, 'default_supplier':1, 'default_customer':0}" domain="[('supplier','=',True)]" attrs="{'required': [('is_quantity_copy', '=', 'none')]}"/>
                         <field name="account_analytic_id" colspan="2" groups="analytic.group_analytic_accounting" attrs="{'readonly': [('state','not in',('draft'))]}"/>
                     </group>