aks bastion: correctly set the contents of the kubeconfig

Signed-off-by: Steve Kuznetsov <stekuznetsov@microsoft.com>

Author: stevekuznetsov

src/aks-preview/azext_aks_preview/bastion/bastion.py

@@ -186,14 +186,14 @@ def aks_bastion_set_kubeconfig(kubeconfig_path, port):
     with open(kubeconfig_path, "r") as f:
         data = yaml.load(f, Loader=yaml.SafeLoader)
     current_context = data["current-context"]
-    for cluster in data["clusters"]:
+    for i, cluster in enumerate(data["clusters"]):
         if cluster["name"] == current_context:
             server = cluster["cluster"]["server"]
             hostname = urlparse(server).hostname
             # update the server URL to point to the local port
-            cluster["cluster"]["server"] = f"https://localhost:{port}/"
+            data["clusters"][i]["cluster"]["server"] = f"https://localhost:{port}/"
             # set the tls-server-name to the hostname
-            cluster["cluster"]["tls-server-name"] = hostname
+            data["clusters"][i]["cluster"]["tls-server-name"] = hostname
             break
     with open(kubeconfig_path, "w") as f:
         yaml.dump(data, f)