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>

test/zdtm.py

@@ -1052,7 +1052,10 @@ class criu:
 			os.close(status_fds[1])
 			if os.read(status_fds[0], 1) != b'\0':
 				ret = ret.wait()
-				raise test_fail_exc("criu %s exited with %s" % (action, ret))
+				if self.__test.blocking():
+					raise test_fail_expected_exc(action)
+				else:
+					raise test_fail_exc("criu %s exited with %s" % (action, ret))
 			os.close(status_fds[0])
 			return ret