BUG #15078: Fix update issue with PointSprite plugin.

This reverts part of the change introduced by commit d4d4adb763. Fixes
the issue with RenderMode changes not having any effect.

Change-Id: I2c8d3d032074df55177f2a4820e1845a162872c2
Merge topic '15078_fix_point_sprite' into next

4979c43a BUG #15078: Fix update issue with PointSprite plugin.