Drop lxc-setcap and lxc-setuid

As discussed earlier this week, lxc-setcap and lxc-setuid have been
in pretty bad shape lately. Most if not all distros recommend against
using them or don't ship them at all.

With the ongoing work to get user namespaces working in upstream LXC,
we think it's best to drop those two now as we prepare to land proper
setuid helpers to deal with user namespaces.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>