Normal lxc-start usage tends to be "lxc-start -n name [-P lxcpath]".
This causes $lxcpath/$name/config to be the configuration for the
container. However, lxc-start is more flexible than that. You can
specify a custom configuration file, in which case $lxcpath/$name/config
is not used. You can also (in addition or in place of either of these)
specify configuration entries one-by-one using "-s lxc.utsname=xxx".
To support this using the API, if we are not using
$lxcpath/$name/config then we put ourselves into a custom lxcpath
called (configurable using LXCPATH) /var/lib/lxc_anon. To stop a
container so created, then, you would use
lxc-stop -P /var/lib/lxc_anon -n name
TODO: we should walk over the list of &defines by hand and set them
using c->set_config_item. I haven't done that in this patch.