build: ignore coverallsapp upload errors
build: ignore coverallsapp upload errors

I've been seeing at least one coveralls upload error per week.  The
hassle of investigating currently outweighs the benefit of catching
errors/misconfigurations on our end.  Ignore errors for now.

Signed-off-by: Kevin Locke <ffb4761cba839470133bee36aeb139f58d7dbaa9@kevinlocke.name>

kevinoid/appveyor-status,kevinoid/appveyor-status,kevinoid/appveyor-status