HPCC-10444 Regression Suite failed in overnight build and test

Fix cluster listing problem

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>

testing/regress/regress

@@ -70,6 +70,7 @@ if __name__ == "__main__":
     try:
         if 'clusters' in args:
             Clusters = ['setup']
+            regress = Regression(args.config, args.loglevel, suiteDir)
             for cluster in regress.config.Clusters:
                 Clusters.append(str(cluster))
             print "Avaliable Clusters: "