tests: add unprivileged mqueue sysctl tests

Add a test to verify that when a ipc namespace is created in a user
namespace, the mqueue sysctl files should are writable by the owner of
the user namespace.

Link: https://lore.kernel.org/lkml/20210827095027.5662-1-ran.xiaokai@zte.com.cn
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
[christian.brauner@ubuntu.com: edit commit message]
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
3 files changed