Move import to the function that uses it

Only Python 2.x is having problems with this import so for now
the fix would be to move the import to the function that uses cluster

django_q/tasks.py

@@ -9,7 +9,6 @@ from django.utils import timezone
 
 # local
 from django_q.signing import SignedPackage
-from django_q import cluster
 from django_q.conf import Conf, logger
 from django_q.models import Schedule, Task
 from django_q.humanhash import uuid
@@ -672,13 +671,17 @@ class Async(object):
 
 
 def _sync(pack):
+    # Python 2.6 is unable to handle this import on top of the file
+    # because it creates a circular dependency between tasks and cluster
+    from django_q.cluster import worker, monitor
+
     """Simulate a package travelling through the cluster."""
     task_queue = Queue()
     result_queue = Queue()
     task = SignedPackage.loads(pack)
     task_queue.put(task)
     task_queue.put('STOP')
-    cluster.worker(task_queue, result_queue, Value('f', -1))
+    worker(task_queue, result_queue, Value('f', -1))
     result_queue.put('STOP')
-    cluster.monitor(result_queue)
+    monitor(result_queue)
     return task['id']