pypyPackages.random2: disable tests
fix eval
mesos: fix build
pypy: compile also curses
Disable Xen kernel builds

Xen itself is currently broken in Nixpkgs, so building kernels for it
is kind of pointless.
lttng-modules: Mark as broken

These do not build for any kernel:

  http://hydra.nixos.org/eval/1149989?filter=lttng&compare=1149981
Remove numerous failing kernel packages from Hydra

  http://hydra.nixos.org/eval/1149989?filter=linuxPackages