devices file: do not clear PVID of unread devices

In a certain disconnected state, a block device is present on
the system, can be opened, reports a valid size, reports the
correct device id (wwid), and matches a devices file entry.
But, reading the device can still fail.  In this case,
device_ids_validate() was misinterpreting the read error as
the device having no data/label on it (and no PVID).
The validate function would then clear the PVID from the
devices file entry for the device, thinking that it was
fixing the devices file (making it consistent with the on disk
state.)  Fix this by not attempting to check and correct a
devices file entry that cannot be read.  Also make this case
explicit in the hints validation code (which was doing the
right thing but indirectly.)

0 files changed, 0 insertions, 0 deletions