[FIX] missing a threading.RLock in RegistryManager.get():

if no registry exists and several calls to RegistryManager.get() are called at the same time
by several threads, several registries will be created one after the other and only the last
one will be kept in cls.registries

lp bug: https://launchpad.net/bugs/1238560 fixed

bzr revid: guewen.baconnier@camptocamp.com-20131011092632-b267vhdadh7q9som

openerp/modules/registry.py

@@ -185,6 +185,7 @@ class RegistryManager(object):
     @classmethod
     def get(cls, db_name, force_demo=False, status=None, update_module=False):
         """ Return a registry for a given database name."""
+        with cls.registries_lock:
             try:
                 return cls.registries[db_name]
             except KeyError: