Fix verify-flags lists to account for flag changes

hack/verify-flags/excluded-flags.txt

@@ -1,6 +1,5 @@
 check_version_skew
 concurrent_rc_syncs
-etcd_mutation_timeout
 file_content
 file_mode
 file_owner
@@ -8,8 +7,6 @@ file_perm
 fs_type
 gke_context
 host_port_endpoints
-kubecfg_file
-kube_master_url
 max_in_flight
 max_par
 new_file_0644

hack/verify-flags/known-flags.txt

@@ -88,6 +88,7 @@ enable-debugging-handlers
 enable-hostpath-provisioner
 enable-server
 etcd-config
+etcd-mutation-timeout
 etcd-prefix
 etcd-server
 etcd-servers
@@ -157,6 +158,7 @@ kube-api-burst
 kube-api-qps
 kube-master
 kube-reserved
+kubecfg-file
 kubectl-path
 kubelet-address
 kubelet-cadvisor-port
@@ -174,6 +176,8 @@ kubelet-read-only-port
 kubelet-root-dir
 kubelet-sync-frequency
 kubelet-timeout
+kube-master
+kube-master-url
 kubernetes-service-node-port
 label-columns
 last-release-pr