Move stray magic values to literals.py in the checkout app. gh-issue #225.

mayan/apps/checkouts/tasks.py

@@ -5,9 +5,9 @@ import logging
 from lock_manager import Lock, LockError
 from mayan.celery import app
 
+from .literals import CHECKOUT_EXPIRATION_LOCK_EXPIRE
 from .models import DocumentCheckout
 
-LOCK_EXPIRE = 50
 logger = logging.getLogger(__name__)
 
 
@@ -17,7 +17,7 @@ def task_check_expired_check_outs():
     lock_id = 'task_expired_check_outs'
     try:
         logger.debug('trying to acquire lock: %s', lock_id)
-        lock = Lock.acquire_lock(lock_id, LOCK_EXPIRE)
+        lock = Lock.acquire_lock(name=lock_id, timeout=CHECKOUT_EXPIRATION_LOCK_EXPIRE)
         logger.debug('acquired lock: %s', lock_id)
         DocumentCheckout.objects.check_in_expired_check_outs()
         lock.release()