build_chroot: *: Add lens dependency

It was missing. Tested locally.
build_chroot: Precise: No need to install cabal twice

It was installed twice via apt, the second one doing nothing.
build_chroot: Precise: Fix dependencies

We require newer dependencies than listed in Precise.
Versions taken from Wheezy. Tested locally.
Cabal: Relax deps to text-0.11.1.13

This way we can include Ubuntu 12.04's version of text.
Tested locally.