Fix FINISHED status check on challenges with no status (#496)
Fix FINISHED status check on challenges with no status (#496)

Fixes bug osmlab/maproulette#625
mvexel/maproulette2,maproulette/maproulette2,Crashfreak/maproulette2,maproulette/maproulette2,maproulette/maproulette2,mvexel/maproulette2,mgcuthbert/maproulette2,mgcuthbert/maproulette2,Crashfreak/maproulette2