Only check last directory when discovering checkpoint number (#5756)
Only check last directory when discovering checkpoint number (#5756)

* Only check last directory when discovering checkpoint number

Signed-off-by: Devin Trejo <bdd2ef59347d67e0b84c76a665b4f4b4fe895336@palantir.com>

* Comments for checkpointNum

Signed-off-by: Devin Trejo <bdd2ef59347d67e0b84c76a665b4f4b4fe895336@palantir.com>

kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,kangwoo/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,alileza/prometheus,Gouthamve/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,alileza/prometheus,Gouthamve/prometheus,kangwoo/prometheus,prometheus/prometheus