cleanup: fix incorrect logging info when volume is already mounted

Author: andyzhangx

pkg/blob/nodeserver.go

@@ -133,6 +133,7 @@ func (d *Driver) NodePublishVolume(ctx context.Context, req *csi.NodePublishVolu
 	}
 	if mnt {
 		klog.V(2).Infof("NodePublishVolume: volume %s is already mounted on %s", volumeID, target)
+		isOperationSucceeded = true
 		return &csi.NodePublishVolumeResponse{}, nil
 	}
 
@@ -329,6 +330,7 @@ func (d *Driver) NodeStageVolume(ctx context.Context, req *csi.NodeStageVolumeRe
 	}
 	if mnt {
 		klog.V(2).Infof("NodeStageVolume: volume %s is already mounted on %s", volumeID, targetPath)
+		isOperationSucceeded = true
 		return &csi.NodeStageVolumeResponse{}, nil
 	}