change Beginner Task Tag to just @beginner

because the _task suffix is redundant, this is a task tag.

Change-Id: Ifb0b13b9394ef31424de167a6d100f17b8f9de58
diff --git a/app/soc/modules/gci/tasks/bulk_create.py b/app/soc/modules/gci/tasks/bulk_create.py
index 55af76f..755b923 100644
--- a/app/soc/modules/gci/tasks/bulk_create.py
+++ b/app/soc/modules/gci/tasks/bulk_create.py
@@ -54,7 +54,7 @@
                 'task_type', 'tags']
 
 # special task used to specify that the created task is a beginner task
-BEGINNER_TASK_TAG = '@beginner_task'
+BEGINNER_TASK_TAG = '@beginner'
 
 
 class BulkCreateTask(object):