ubuntu: Add comment about the mounting profile

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
lxc-test-concurrent: initialize saveptr before use

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Make public API string method parameters const where possible.

Signed-off-by: James Hunt <james.hunt@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>