zdtm.py: expect test to fail if crfail flag is set

Suppress the false positive fail in criu-live-migration job:
https://ci.openvz.org/job/CRIU/job/criu-live-migration/job/criu-dev/1796/



[criu]# ./test/zdtm.py run -t zdtm/static/overmounted_file -f uns --lazy-migrate

=== Run 1/1 ================ zdtm/static/overmounted_file
=================== Run zdtm/static/overmounted_file in uns ====================
Start test
Test is SUID
./overmounted_file --pidfile=overmounted_file.pid --outfile=overmounted_file.out --dirname=overmounted_file.test
Run criu dump
Test zdtm/static/overmounted_file FAIL at criu dump exited with 1 ######
Send the 9 signal to  49
Wait for zdtm/static/overmounted_file(49) to die for 0.100000

Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>