guard against sites missing expire headers #1430
guard against sites missing expire headers #1430

JeroenVdb/sitespeed.io,sitespeedio/sitespeed.io,beenanner/sitespeed.io,sitespeedio/sitespeed.io,sitespeedio/sitespeed.io,JeroenVdb/sitespeed.io,sitespeedio/sitespeed.io,JeroenVdb/sitespeed.io,beenanner/sitespeed.io,beenanner/sitespeed.io