[X2Go-Project] apt-cacher-ng updated to wheezy-backports version on japsand

Hi

Our builds have been running into problems when fetching binary Debian packages lately.

Error messages looked like this: E: Failed to fetch http://example.com/debian/pool/main/*/.deb: 500 Connection timeout

This seems to have been caused by a known (and subsequently) fixed bug, c.f., https://bugs.debian.org/717832

I decided not to manually apply the patch and rebuild the package, but fetch the fixed version from Debian backports, which we're already using anyway.

Hopefully Debian builds will be more stable in the future, at least when fetching packages. (And qemubuilder be the biggest source of problems once again...)

Mihai