lxc.conf.sgml.in: fill in missing configuration file statements

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
api_clone: call is_stopped_locked() to avoid deadlock.

Technically as Dwight has mentioned we should probably drop the locking
from api_state() altogether, since those are protected through the
lxc command system.

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