[IMP] various: use odoo for imports instead of openerp and update class names

addons/pos_cache/models/pos_cache.py

@@ -1,9 +1,10 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
+
 from ast import literal_eval
 
-from openerp import models, fields, api
-from openerp.tools import pickle as cPickle
+from odoo import models, fields, api
+from odoo.tools import pickle as cPickle
 
 
 class pos_cache(models.Model):