Property UdevDevice.id not defined

[Abel Deuring]

When we store data about a device in a given submission, we must set the column HWSubmissionDevice.hal_device_id to an interger. For HAL data, we use the value of the attribute "id" in <device id="123">; the udev data does not provide such an ID for deices. We can instead assign udev devices a number when we parse the <udev> node.