registered depth only works sometimes with openni_launch
I've noticed that when I use openni_launch, I can examine the depth_registered/image_raw, the rgb image, and even the IR image (if the rgb image topic is not also subscribed to). But, the depth_registered/points topic often reports nothing. Sometimes, I have to retry openni_launch up to 10 times before I finally get out a point cloud. I looked through this, and I can't see where any nodelet would have a race condition, but it seems that that might be the case. At first, I thought unplugging the Kinect helped -- but that doesn't seem to be a consistent fix. I also can run the openni_viewer that is installed with openni, and I get out the correct pointcloud, so I'm not sure why openni_launch doesn't always publish on depth_registered/points.