Close file for windows platform
Close file for windows platform

Windows needs files that are being deleted to be closed.

Fixes: https://github.com/prometheus/prometheus/issues/3956

Signed-off-by: Goutham Veeramachaneni <caf616f34019d2c106581c18639c41d1bae35076@iith.ac.in>

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