Fixing the Endpoint parameter issue

Author: nemanja88

src/ServiceManagement/HDInsight/Commands.HDInsight/Model/GetAzureHDInsightClusters/AzureHDInsightClusterCommandBase.cs

@@ -47,7 +47,12 @@ internal IHDInsightClient GetClient()
                 this.CurrentSubscription,
                 client.GetEnvironmentOrDefault(this.CurrentSubscription.Environment),
                 client.Profile);
-            subscriptionCredentials.Endpoint = this.Endpoint;
+
+            if (this.Endpoint.IsNotNull())
+            {
+                subscriptionCredentials.Endpoint = this.Endpoint;               
+            }
+
             var clientInstance = ServiceLocator.Instance.Locate<IAzureHDInsightClusterManagementClientFactory>().Create(subscriptionCredentials);
             clientInstance.SetCancellationSource(this.tokenSource);
             if (this.Logger.IsNotNull())