verify: escape '/' in state file name to '.'

verify: escape '/' in state file name to '.'

If the job name includes a front slash, then we get an error when
we try to create the state file name:

	fio: open state file: No such file or directory

Change the '/' to '.' instead, so we generate a valid file name.

Signed-off-by: Jens Axboe <axboe@fb.com>