Bugfix #479: Allow non-admin users get devices passthrough information

The API /host/devices is used in many places (such as to create a SCSI
FC pool or to list the PCI passthrough devices).
As the PCI passthrough devices might be accessible for non-admin users
the authorization configuration to that API was reset.

Signed-off-by: Aline Manera <alinefm@linux.vnet.ibm.com>