[IMP] base: timezone handling in server actions.

Give access to `pytz.timezone` (as `timezone`) in `ir.actions.server`
records. Usefull when dealing with date(time)s.

openerp/addons/base/ir/ir_actions.py

@@ -26,6 +26,7 @@ import os
 import time
 import datetime
 import dateutil
+import pytz
 
 import openerp
 from openerp import SUPERUSER_ID
@@ -944,6 +945,9 @@ class ir_actions_server(osv.osv):
             'time': time,
             'datetime': datetime,
             'dateutil': dateutil,
+            # NOTE: only `timezone` function. Do not provide the whole `pytz` module as users
+            #       will have access to `pytz.os` and `pytz.sys` to do nasty things...
+            'timezone': pytz.timezone,
             # orm
             'env': env,
             'model': model,