remove redundant parameter in comments
remove redundant parameter in comments

In function report, there is no paramter task_id, however, the
comments contain it, so remove it from comments.

Change-Id: I7ad36f305591bd281d58a8c0cd9777a71f9e17b2

openstack/rally,yeming233/rally,openstack/rally,openstack/rally,yeming233/rally,openstack/rally