Oops - correctly get the hostname from os.Hostname when the network is down
Oops - correctly get the hostname from os.Hostname when the network is down

BUG=575775

Review URL: https://codereview.chromium.org/1579023003

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go