util: quieten virSCSIHostGetUniqueId
util: quieten virSCSIHostGetUniqueId

The only caller of this function ignores failure
and just sets the unique_id to -1.

Failing to read the file is likely to the device no longer
being present, not a real error.

Stop reporting errors in this function.

https://bugzilla.redhat.com/show_bug.cgi?id=1692100

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Reviewed-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,zippy2/libvirt,nertpinx/libvirt,jfehlig/libvirt,libvirt/libvirt,olafhering/libvirt,crobinso/libvirt,olafhering/libvirt,jfehlig/libvirt,libvirt/libvirt,olafhering/libvirt,crobinso/libvirt,crobinso/libvirt,nertpinx/libvirt,jfehlig/libvirt,libvirt/libvirt,zippy2/libvirt,nertpinx/libvirt,zippy2/libvirt,zippy2/libvirt,crobinso/libvirt,libvirt/libvirt,nertpinx/libvirt