tests/migration: fix unreachable path in stress test

If stressone() or stress() exits it's because of a failure
because the test runs forever otherwise, so change stressone
and stress type to void to make the exit_failure() as the exit
function of main().

Signed-off-by: Mao Zhongyi <maozhongyi@cmss.chinamobile.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200603080904.997083-3-maozhongyi@cmss.chinamobile.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
1 file changed