lxc_init: don't fail on bad signals

Changelog: Jan 22: as Michael Warfield pointed out, we should only
ignore EINVAL, since EFAULT points to a more serious problem.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
lxc-start-ephemeral: require root

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
doc: Try to clear some confusion about lxc.conf

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

This also fixes unprivileged use of lxc-snapshot and lxc-rename.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>