VZ containers: Make fds proper closing vz_spawn_execve, vz_enter_execve
VZ containers: Make fds proper closing vz_spawn_execve, vz_enter_execve

Fix it, so vz_enter test is now passed.

Signed-off-by: Alexander Burluka <e1a296dbcd92383e62ed2d193750f7aed5ae3091@parallels.com>

LK4D4/libct,hallyn/libct,LK4D4/libct,hallyn/libct,xemul/libct,xemul/libct,xemul/libct,avagin/libct,avagin/libct,hallyn/libct,LK4D4/libct,avagin/libct,xemul/libct