Fix juju kubernetes-master starting services before TLS certs are saved

master: Fix start_master args

cluster/juju/layers/kubernetes-master/reactive/kubernetes_master.py

@@ -268,10 +268,10 @@ def idle_status():
         hookenv.status_set('active', 'Kubernetes master running.')
 
 
-@when('etcd.available', 'certificates.server.cert.available',
+@when('etcd.available', 'tls_client.server.certificate.saved',
       'authentication.setup')
 @when_not('kubernetes-master.components.started')
-def start_master(etcd, tls):
+def start_master(etcd):
     '''Run the Kubernetes master components.'''
     hookenv.status_set('maintenance',
                        'Configuring the Kubernetes master services.')