Comment 5 for bug 1531150

True, it's a partial fix only (fixes the part that affected me). We still need to fix /usr/lib/landscape/apt-update to properly report the error from apt-get.

The setup of the proxy configuration for apt is usually done during the initial installation of a machine, so I doubt the problem would go unnoticed for long (you can't even install landscape using apt unless the proxy is setup correctly).