discovery/file: fix logging (#4178)
discovery/file: fix logging (#4178)

Signed-off-by: Simon Pasquier <38e2d22e48be18381a59028f88390cad04670376@redhat.com>
alileza/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,kangwoo/prometheus,amorken/prometheus,Gouthamve/prometheus,kangwoo/prometheus,Gouthamve/prometheus,Gouthamve/prometheus,kangwoo/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,amorken/prometheus,keegancsmith/prometheus,prometheus/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,amorken/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,keegancsmith/prometheus,amorken/prometheus,alileza/prometheus,Gouthamve/prometheus,prometheus/prometheus