Change DisableDevice error to warning

Change-Id: I3b6e586610d3f20e86b7f20bf099b6ee2451d11a

Author: mattcary

pkg/gce-pd-csi-driver/node.go

@@ -397,9 +397,9 @@ func (ns *GCENodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUns
 		klog.Errorf("Failed to find device path for volume %s. Device may not be detached cleanly (error is ignored and unstaging is continuing): %v", volumeID, err.Error())
 	} else {
 		if devFsPath, err := filepath.EvalSymlinks(devicePath); err != nil {
-			klog.Errorf("filepath.EvalSymlinks(%q) failed when trying to disable device: %w (ignored, unstaging continues)", devicePath, err)
+			klog.Warningf("filepath.EvalSymlinks(%q) failed when trying to disable device: %w (ignored, unstaging continues)", devicePath, err)
 		} else if err := ns.DeviceUtils.DisableDevice(devFsPath); err != nil {
-			klog.Errorf("Failed to disabled device %s (aka %s) for volume %s. Device may not be detached cleanly (error is ignored and unstaging is continuing): %w", devicePath, devFsPath, volumeID, err)
+			klog.Warningf("Failed to disabled device %s (aka %s) for volume %s. Device may not be detached cleanly (ignored, unstaging continues): %w", devicePath, devFsPath, volumeID, err)
 		}
 	}