Make Travis check lint output properly
Make Travis check lint output properly

Previously lint errors wouldn't fail
the build.

This closes #788.

keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/kbfs,keybase/client,keybase/client