Fix expire and false_positive not setting properly.
Fix expire and false_positive not setting properly.

Code was broken using a non-existent method. This change makes them use
the .set() method.

tiegz/ThreatExchange,RyPeck/ThreatExchange,mgoffin/ThreatExchange,RyPeck/ThreatExchange,RyPeck/ThreatExchange,theCatWisel/ThreatExchange,tiegz/ThreatExchange,tiegz/ThreatExchange,tiegz/ThreatExchange,wxsBSD/ThreatExchange,wxsBSD/ThreatExchange,tiegz/ThreatExchange,wxsBSD/ThreatExchange,RyPeck/ThreatExchange,wxsBSD/ThreatExchange,mgoffin/ThreatExchange,tiegz/ThreatExchange,wxsBSD/ThreatExchange,theCatWisel/ThreatExchange,RyPeck/ThreatExchange,RyPeck/ThreatExchange,wxsBSD/ThreatExchange,theCatWisel/ThreatExchange,mgoffin/ThreatExchange,mgoffin/ThreatExchange,theCatWisel/ThreatExchange,theCatWisel/ThreatExchange,arirubinstein/ThreatExchange,mgoffin/ThreatExchange,mgoffin/ThreatExchange,theCatWisel/ThreatExchange