Bug 1501048 - remove bogus code; r=bstack

This was likely the result of a merge error.  The code is not needed, and
anyway appears before a docstring.

--HG--
extra : rebase_source : a8ecb8596abc498e2e74d4fb903e3087dec5a381

taskcluster/taskgraph/actions/retrigger.py

@@ -39,8 +39,6 @@ logger = logging.getLogger(__name__)
     ],
 )
 def retrigger_decision_action(parameters, graph_config, input, task_group_id, task_id, task):
-    decision_task_id, full_task_graph, label_to_taskid = fetch_graph_and_labels(
-        parameters, graph_config)
     """For a single task, we try to just run exactly the same task once more.
     It's quite possible that we don't have the scopes to do so (especially for
     an action), but this is best-effort."""