[FIX] base: field 'Type' readonly

The field 'Type' should always be readonly since:
- it must not be changed for standard models
- its value must be 'Custom Object' for a custom model

opw-706130

openerp/addons/base/ir/ir_model_view.xml

@@ -35,7 +35,7 @@
                             <field name="transient" attrs="{'readonly': [('id', '!=', False)]}"/>
                         </group>
                         <group>
-                            <field name="state" attrs="{'readonly': [('id', '!=', False)]}"/>
+                            <field name="state" readonly="1"/>
                             <field name="modules"/>
                         </group>
                     </group>