Let NodeUnpublishVolume pass when it cannot find volume

This can happen when the volume is manually unmounted or the kubelet's
volume bread crumbs in the pod's namespace have been manually removed.

Signed-off-by: Dean Roehrich <[email protected]>

pkg/lustre-driver/service/node.go

@@ -21,6 +21,7 @@ package service
 
 import (
 	"os"
+	"strings"
 
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
@@ -121,7 +122,9 @@ func (s *service) NodeUnpublishVolume(
 
 	mounter := mount.New("")
 	notMountPoint, err := mount.IsNotMountPoint(mounter, req.GetTargetPath())
-	if err != nil {
+	if err != nil && strings.Contains(err.Error(), "no such") {
+		// consider it unmounted
+	} else if err != nil {
 		return nil, status.Errorf(codes.Internal, "NodeUnpublishVolume - Mount point check Failed: Error %v", err)
 	} else if !notMountPoint {
 		err := mounter.Unmount(req.GetTargetPath())