zdtm/cgroup02: fix test using ropts instead of opts

In commit 07d259f365f2 ("cgroup: support --cgroup-root on dump too")
criu starts to understand --cgroup-root option on dump, but our
cgroup02 test in cgroup02.desc file sets these opt to /newroot
unintentionaly, as on dump we don't have /newroot dump fails:

https://ci.openvz.org/job/CRIU/job/CRIU-x86_64/branch/criu-dev/989

======================== Run zdtm/static/cgroup02 in h
=========================
Start test
Test is SUID
./cgroup02 --pidfile=cgroup02.pid --outfile=cgroup02.out
--dirname=cgroup02.test
Run criu dump
=[log]=> dump/zdtm/static/cgroup02/30/1/dump.log
------------------------ grep Error ------------------------
(00.023103) Error (criu/cgroup.c:620): cg: failed walking
/proc/self/fd/10/newroot for empty cgroups: No such file or directory
(00.023129) Error (criu/cr-dump.c:1359): Dump core (pid: 30) failed with
-1
(00.023944) Error (criu/cr-dump.c:1675): Dumping FAILED.
------------------------ ERROR OVER ------------------------

So fix this by using restore-only ropts instead of opts.
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm/static/cgroup02.desc

-{'flavor': 'h', 'flags': 'suid', 'opts': '--manage-cgroups --cgroup-root /newroot --cgroup-root name=zdtmtst:/zdtmtstroot'}
+{'flavor': 'h', 'flags': 'suid', 'ropts': '--manage-cgroups --cgroup-root /newroot --cgroup-root name=zdtmtst:/zdtmtstroot'}