Release the camera in surfaceDestroyed().

If the camera is not released, the new client will fail to connect to camera next time. b2042350

samples/ApiDemos/src/com/example/android/apis/graphics/CameraPreview.java

@@ -78,6 +78,7 @@ class Preview extends SurfaceView implements SurfaceHolder.Callback {
         // Because the CameraDevice object is not a shared resource, it's very
         // important to release it when the activity is paused.
         mCamera.stopPreview();
+        mCamera.release();
         mCamera = null;
     }