cluster: remove k8s_token files from zones on write if found

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/cluster/regions.go

@@ -204,6 +204,11 @@ func (z *Zone) SyncRegions() error {
 			} else {
 				err = p.WriteStringFile("none\n", "region")
 			}
+
+			if err == nil {
+				err = p.RemoveFile(RegionClusterTokenFileName)
+			}
+
 			return err != nil
 		})
 	}