fluentd-ui: Fix env variable handling
fluentd-ui: Fix env variable handling

iantalarico/google-fluentd,iantalarico/google-fluentd,iantalarico/google-fluentd,GoogleCloudPlatform/google-fluentd,GoogleCloudPlatform/google-fluentd,treasure-data/omnibus-td-agent,treasure-data/omnibus-td-agent,treasure-data/omnibus-td-agent,GoogleCloudPlatform/google-fluentd