Fix locking related bug in Stats.ReadFile
Fix locking related bug in Stats.ReadFile

Reviewed-on: https://code.launchpad.net/~jsing/canonical-is-hockeypuck/+git/hockeypuck/+merge/367694
Reviewed-by: Stuart Bishop <50accf0533a8b56513bf03682cc7589e9bf77857@canonical.com>
Reviewed-by: Casey Marshall <aabf98ed72e2fd303f082113bb2334c57894a354@canonical.com>

cmars/hockeypuck,cmars/hockeypuck