Setup failing cryptically on Debian and not reporting exact error to user

[katebee]

When running setup-app on Debian, the script will run setup-cert and quietly fail due to missing JAVA_HOME.

Running setup-cert separately will report the error to the user, however the error seems to be swallowed when running the main script, setup-app.

https://github.com/guardian/dev-nginx/blob/master/script/setup-cert#L30

[AWare]

This still fails silently on Ubuntu, and gets further- but also fails silently once the offending java block is removed from setup-cert