zip_archive: reject files that don't start with an LFH signature. am: dbacd826a1 am: 368ec42fa8 am: 6dbd1db1cf am: 58c10b2ab9  -s ours am: 2dbba44e2d am: 583a11b339 am: 15d221c0ba am: 377f534697 am: 1cd5954ced am: 4168856cf2 am: 53f49bc4ec am: 66ec509a64  -s ours
am: 000c6825c5  -s ours

Change-Id: I7a9c3faeccb9ff43fa310ffbf9c00124664e9c96