Update grafana/grafana Docker tag to v6.4.4
Update grafana/grafana Docker tag to v6.4.4

trungdtbk/faucet,REANNZ/faucet,mwutzke/faucet,shivarammysore/faucet,mwutzke/faucet,faucetsdn/faucet,trungdtbk/faucet,anarkiwi/faucet,gizmoguy/faucet,anarkiwi/faucet,REANNZ/faucet,gizmoguy/faucet,shivarammysore/faucet,faucetsdn/faucet