Fix multi-company of Property when using root

If user is root, we must use the user in context

issue2054
review41006
(transplanted from 7147b97254308bb63d8d0ac75bbd98c64e509830)

company.py

@@ -188,6 +188,10 @@ class Property(ModelSQL, ModelView):
     def _set_values(self, cursor, user_id, name, model, res_id, val, field_id,
             context=None):
         user_obj = self.pool.get('res.user')
+        if context is None:
+            context = {}
+        if user_id == 0:
+            user_id = context.get('user', user_id)
         user = user_obj.browse(cursor, user_id, user_id, context=context)
         res = super(Property, self)._set_values(cursor, user_id, name, model,
                 res_id, val, field_id, context=context)