Try to be more helpful on container startup failure

This hides some of the confusing "command X failed to receive response"
why are usually caused by another more understandable error.

On failure to start() from lxc-start, a new error message is displayed,
suggesting the user sets logfile and loglevel and if using -d, restarts
the container in the foreground instead.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
doc: Update Japanese man pages for the description of boot and group handling

Update lxc-autostart(1) and lxc.container.conf(5) for commit 015f0dd.

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
doc: Fix typo in lxc-autostart(1)

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
python3: Fix crashes in snapshot()

This makes sure all PyObject structs are always initialized to NULL,
this will fix issues such as (issue #239).

Also add a snapshot/list/restore testcase to the python3 api test code.

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