Read failure of a driver-source URL repo causes repo to be silently ignored

[ydirson]

If an unpacked driver-disk ISO is used through a <driver-source type="url"> in answerfile, and the isRepo() check fails because the directories are not readable, the driver source is silently ignored: no error shown to user, and no diagnostic written to install-log.

Other error cases are likely causing a repo to get silently ignored, we should be more robust.

Found this issue by unpacking the ISO using 7z tool, which unfortunately otherwise seems to be the most practical tool to extract files from an ISO image (with mount requiring root permissions, fuseiso not being universally available, and still needing more manual operations than 7z (correctly) teaches users to expect, and similarly for the more recent udisksctl loop-setup).