Change unsupported fileno() LOG to debug
Change unsupported fileno() LOG to debug

When restoring a volume this log lines is logged
many times but there is nothing to really do or know.

When our backup workers is busy this is just thousands
of lines that doesn't give us anything.

Change-Id: I1f356e16a0d887eba32731e822c1b6da5299965c

mahak/cinder,mahak/cinder,openstack/cinder,openstack/cinder