[FIX] sql: Do no consider a table exists if this is a schema table/view

Before this revision, this is not possible to create a model
with a `_table` set to `domains`, for instance.

odoo/tools/sql.py

@@ -23,7 +23,7 @@ _CONFDELTYPES = {
 
 def table_exists(cr, tablename):
     """ Return whether the given table exists. """
-    query = "SELECT 1 FROM information_schema.tables WHERE table_name=%s"
+    query = "SELECT 1 FROM information_schema.tables WHERE table_name=%s AND table_schema != 'information_schema'"
     cr.execute(query, (tablename,))
     return cr.rowcount