VM builds: Update debian Wheezy image to v7.1.
VM builds: Update debian Wheezy image to v7.1.

Wheezy has been released on June 15th and on all mirrors the SHA256 hash
of Packages.bz2 has changed to reflect the new release, so let's update.

Here is the release announcement from Debian:

http://www.debian.org/News/2013/20130615

It also seems that the versioning scheme has changed in version 7.x, so
they seem to have switched to a two digit versioning scheme. This means,
that the attribute name "debian70..." should really be something like
"debian7...", but I'm keeping the attribute as-is to not break
references.

Signed-off-by: aszlig <ee1aa092358634f9c53f01b5a783726c9e21b35a@redmoonstudios.org>

NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,triton/triton,NixOS/nixpkgs,triton/triton,triton/triton,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs