bring modules/host.go upto 100% test coverage
bring modules/host.go upto 100% test coverage

MrStrong/Sia,mnsl/Sia,mharkus/Sia,rivine/rivine,ChrisSchinnerl/Sia,ericflo/Sia,NebulousLabs/Sia,ChrisSchinnerl/Sia,MrStrong/Sia,rivine/rivine,NebulousLabs/Sia,mharkus/Sia,mtlynch/Sia,johnathanhowell/Sia,mtlynch/Sia,mnsl/Sia,ericflo/Sia