fix(fatal-error): Exit with non-zero exit code for fatal errors
fix(fatal-error): Exit with non-zero exit code for fatal errors

Fixes #244

dannycoates/fxa-oauth-server,moander/fxa-oauth-server,dannycoates/fxa-oauth-server,rishibaldawa/fxa-oauth-server,mozilla/fxa-auth-server,chilts/fxa-oauth-server,moander/fxa-oauth-server,mozilla/fxa-auth-server,mozilla/fxa-auth-server,chilts/fxa-oauth-server,rishibaldawa/fxa-oauth-server,mozilla/fxa-auth-server