06:46:44.191:    24: ERR: fifo_loop.c:52: can't make fifo "fifo_loop.test-00" (errno = 17 (File exists))

Reported-by: Mr Jenkins
travis-ci: success for zdtm: cleanup fifo_loop.test-0*
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>