Put postings in a temporary file during index writing.
Put postings in a temporary file during index writing.

Signed-off-by: Brian Brazil <aadf89994a343dc176a47081f0c0bbea26f0a345@robustperception.io>

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