real timeout org tree lock (#4429)

Hotfix:

Found a significant number of timeout exceptions raised looking to
acquire the OrgTree-LOCK (used by any process needing to build the
in-memory organization tree on first request).

The default timeout of 10 seconds is clearly inadequate. Increasing to
same value (300 or 5 mins) used for the expiration of this lock (to
catch any hung processes holding on to the lock).

portal/models/organization.py

@@ -838,7 +838,7 @@ class OrgTree(object):
     def __init__(self):
         # Maintain a singleton root object and lookup_table
         try:
-            with TimeoutLock(key=ORG_TREE_LOCK_KEY, expires=300):
+            with TimeoutLock(key=ORG_TREE_LOCK_KEY, expires=300, timeout=300):
                 if not OrgTree.root:
                     self.__reset_cache()
         except LockTimeout: