storage_vol_page: fix presets import

In commit 5901e28f we introduce the import presets from
ovirt.node.config for storage_vol, however the correct
path is ovirt.node. This patch fix the presets import.

Change-Id: Ib33b6a3d9248a3a477b3d689a903ae8dabfddd5a
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>