[OWL-240] add func getHostName() in http/zabbix.go
[OWL-240] add func getHostName() in http/zabbix.go

masato25/query,Cepave/open-falcon-backend,masato25/open-falcon-backend,Cepave/query,masato25/open-falcon-backend,Cepave/open-falcon-backend,masato25/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,Cepave/open-falcon-backend,Cepave/query,Cepave/query,Cepave/open-falcon-backend,masato25/query,Cepave/query,Cepave/open-falcon-backend,masato25/open-falcon-backend,masato25/query,masato25/query,masato25/open-falcon-backend