doc: Add Japanese lxc-autostart(1) and update lxc.conf(5)

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Fix coverity-detected memory leak

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>