tests: Silence startone harder

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
tests: Add missing include

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Fix typo to checking newgidmap existing

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