Fix wrong n_trial number in autotvm tutorials' progress bar (apache#4070)

if n_trial is larger then config space.

Author: dati91

tutorials/autotvm/tune_relay_vta.py

@@ -274,7 +274,8 @@ def tune_tasks(tasks,
                 tuner_obj.load_history(autotvm.record.load_from_file(tmp_log_file))
 
         # do tuning
-        tuner_obj.tune(n_trial=min(n_trial, len(tsk.config_space)),
+        n_trial = min(n_trial, len(tsk.config_space))
+        tuner_obj.tune(n_trial=n_trial,
                        early_stopping=early_stopping,
                        measure_option=measure_option,
                        callbacks=[