Disable allowUnfree by default

Fixes #2134.
Replace $HYDRA_DISALLOW_UNFREE with $NIXPKGS_ALLOW_UNFREE

We've never used this environment variable in Hydra (except for a few
days). This is also more consistent with $NIXPKGS_ALLOW_BROKEN.
Add a flag ‘config.allowBroken’
Die tabs die
Revert "Turn on user-controlled wpa-cli on the livecd"

user-controlled wpa-cli requires explicit interface setting for some
reason

This reverts commit c6797b373f379f7a7f8a7da01bdf3f6751f11f2e.
lockdep: refactor into non-kernel package

Lockdep doesn't *really* require the kernel package - just the kernel
sources. It's really a user-space tool just compiled from some portable
code within the kernel, nothing more.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
libseccomp: version 2.1.1

Signed-off-by: Austin Seipp <aseipp@pobox.com>