[Reviewer: Ellie] Multiple domain support

[mirw]

Ellie,

Please can you review my changes for multiple domain support?

Thanks,

Matt

[eleanor-merry]

There's 4 slightly different ways here of adding a parameter to the DAEMON_ARGs. Can you tidy this up as part of this fix so that they match? Also, I assume there isn't a problem here if $additional_home_domains doesn't exist?

[mirw]

It's fine if additional_home_domains doesn't exist - it's just blank and fails the test.

Let's discuss on Monday about commonizing the ways of adding a parameter to DAEMON_ARGS. I think the if ... then ... fi vs [ ! ... ] || ... distinction makes sense - the former is better for more complex expressions and the latter for simpler. The ..._arg approach vs directly manipulating DAEMON_ARGS is more interesting.

[eleanor-merry]

Couple of minor questions, otherwise fine