Changed test failure handler to Fatalf(), added comment
Changed test failure handler to Fatalf(), added comment

Gouthamve/prometheus,AlekSi/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,brancz/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,Conorbro/prometheus,alileza/prometheus,alileza/prometheus,brancz/prometheus,brancz/prometheus,amorken/prometheus,keegancsmith/prometheus,AlekSi/prometheus,keegancsmith/prometheus,kangwoo/prometheus,amorken/prometheus,amorken/prometheus,prometheus/prometheus,keegancsmith/prometheus,Conorbro/prometheus,Stackdriver/stackdriver-prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,Conorbro/prometheus,Stackdriver/stackdriver-prometheus,Stackdriver/stackdriver-prometheus,Conorbro/prometheus,keegancsmith/prometheus,kangwoo/prometheus,alileza/prometheus,kangwoo/prometheus,keegancsmith/prometheus,prometheus/prometheus,AlekSi/prometheus,Stackdriver/stackdriver-prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,Gouthamve/prometheus,brancz/prometheus,amorken/prometheus,AlekSi/prometheus,kangwoo/prometheus,alileza/prometheus