Debian multi-arch support fix

In Debian Squeeze and previous, 'dpkg --print-foreign-architectures' fails and can be used to check for multi-arch.

If 'dpkg --print-foreign-architectures' fails, the format string should be 'Package' and when it succeeds, 'binary:Package' is used instead.

Tested on Debian Squeeze, Debian Wheezy and Ubuntu 13.04