When containers request to be daemonized, close-all-fd is
set to true.  But when we switched ot daemonize-by-default we didn't
set close-all-fd by default.

Fix that.  In order to do that we have to always have a lxc_conf
object.  As a consequence, after this patch we can drop a bunch
of checks for c->lxc_conf existing.  We should consider removing
those.  This patch does not do that.

This should close https://github.com/lxc/lxc/issues/354Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>