Allow loading of some configuration to fail

Common misconfigurations on the server side means that $HOME may point to the privileged use the application was running as before it dropped privileges. Similarly, the system config file may not always be readable.

I've used `_gently()` as that's the name git often uses for this type of thing. I've also extended the original issue of `EACCES` to fail for whatever reason, as the general feeling seems to be that it's ok for the system to be in a bad state as long as we ignore it.