vzctl: allow upstream to safely stop container when setns is available

The test preventing the execution of in-container reboot right now just
checks whether or not we are running an upstream Linux Kernel. However,
it is perfectly possible to gracefuly stop the container if joining the
pid namespace is possible.

Update the test to reflect that.

Signed-off-by: Glauber Costa <glommer@parallels.com>
1 file changed