[FIX] base: correct inheritance application

While `apply_inheritance_specs` apply most of its changes inplace, it may
completely replace the `arch_tree` if the root node is replaced.
This new root node wasn't used for `primary` views that inherit from
another.

openerp/addons/base/ir/ir_ui_view.py

@@ -536,10 +536,9 @@ class view(osv.osv):
             parent_view = self.read_combined(
                 cr, uid, v.inherit_id.id, fields=fields, context=context)
             arch_tree = etree.fromstring(parent_view['arch'])
-            self.apply_inheritance_specs(
+            arch_tree = self.apply_inheritance_specs(
                 cr, uid, arch_tree, view_arch, parent_view['id'], context=context)
 
-
         if context.get('inherit_branding'):
             arch_tree.attrib.update({
                 'data-oe-model': 'ir.ui.view',