[PATCH] Avoid devices with non existent metadata

[Joel Granados Moreno <jgranado redhat com>]

Hello

When we are listing the pvs in a rhel4 system installation there is a
possibility of receiving non-sense in the device name.  This happens
when the metadata present on the device is no present or otherwise not
readable.  This patch avoids this when reading PVs.

Review Greatly appreciated.

Regards

--
Joel Andres Granados
Brno, Czech Republic, Red Hat.