fix syntax error

config.json.example

@@ -3,7 +3,7 @@
   "bridge": "br-client",
   "mesh-vpn": [ "mesh-vpn" ],
   "mesh-wlan": [ "ibss0", "mesh0" ],
-  "fastd_socket": "/var/run/fastd.mesh_vpn.socket"
+  "fastd_socket": "/var/run/fastd.mesh_vpn.socket",
   "rate_limit": 30,
   "rate_limit_burst": 10
 }