adding timestamp after metric value, to match latest graphite(0.9.12 or ...

adding timestamp after metric value, to match latest graphite(0.9.12 or later) plain text protocol, as described below:
http://graphite.readthedocs.org/en/latest/feeding-carbon.html#the-plaintext-protocol
>The data sent must be in the following format: \<metric path\> \<metric value\> \<metric timestamp\>.