Fix auth-mode

reactive/kubernetes-keystone.py

@@ -81,9 +81,8 @@ def setup_authentication():
 
     # CHECKME: do we need authorization-mode Webhook?
     # get current value for authorization-mode
-    cmd = ['snap', 'get', 'kube-apiserver',
-           'authorization-mode']
-    auth_mode = check_output(cmd).decode('utf-8')
+    cmd = ['snap', 'get', 'kube-apiserver', 'authorization-mode']
+    auth_mode = check_output(cmd).decode('utf-8').strip()
     if 'Webhook' not in auth_mode:
         if auth_mode: auth_mode += ','
         auth_mode += 'Webhook'