[CRIU] [vdso] New vdso series failing the tests

[Cyrill Gorcunov]

Dima, the recent series for vdso rework ruined tests on old
kernels, such as 3.10 series.

https://ci.openvz.org/job/CRIU/job/CRIU-virtuozzo/job/criu-dev/5398/

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[root at vz7 criu]# git bisect good
0918c7667647ac16d6082764f78d1c0b407f3536 is the first bad commit
commit 0918c7667647ac16d6082764f78d1c0b407f3536
Author: Dmitry Safonov <dima at arista.com>
Date:   Thu Jul 25 23:01:10 2019 +0100

    vdso/restorer: Always track vdso/vvar positions in vdso_maps_rt
    
    For simplicity, make them always valid in restorer.
    rt->vdso_start will be used to calculate gettimeofday() address.
    
    Signed-off-by: Dmitry Safonov <dima at arista.com>
    Signed-off-by: Andrei Vagin <avagin at gmail.com>
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I think it is due to lack of vvar zone on those kernels. Please take a look.

	Cyrill