Handle missing app uuid or app uuid that is None gracefully.
Handle missing app uuid or app uuid that is None gracefully.

This fixes SENTRY-131

beeftornado/sentry,jean/sentry,alexm92/sentry,gencer/sentry,JackDanger/sentry,mvaled/sentry,ifduyue/sentry,alexm92/sentry,mitsuhiko/sentry,zenefits/sentry,zenefits/sentry,JamesMura/sentry,mitsuhiko/sentry,BuildingLink/sentry,JackDanger/sentry,looker/sentry,ifduyue/sentry,fotinakis/sentry,BuildingLink/sentry,mvaled/sentry,zenefits/sentry,jean/sentry,JamesMura/sentry,ifduyue/sentry,looker/sentry,BuildingLink/sentry,JamesMura/sentry,jean/sentry,alexm92/sentry,mvaled/sentry,mvaled/sentry,BuildingLink/sentry,looker/sentry,zenefits/sentry,fotinakis/sentry,jean/sentry,gencer/sentry,gencer/sentry,mvaled/sentry,looker/sentry,ifduyue/sentry,zenefits/sentry,gencer/sentry,ifduyue/sentry,BuildingLink/sentry,looker/sentry,beeftornado/sentry,fotinakis/sentry,JamesMura/sentry,jean/sentry,beeftornado/sentry,JamesMura/sentry,fotinakis/sentry,mvaled/sentry,JackDanger/sentry,gencer/sentry