OpenGL2: Reimplement soft overbright to avoid a framebuffer blit.

code/renderergl2/tr_local.h

@@ -1620,7 +1620,6 @@ typedef struct {
 	image_t					*renderDepthImage;
 	image_t					*pshadowMaps[MAX_DRAWN_PSHADOWS];
 	image_t					*textureScratchImage[2];
-	image_t					*screenScratchImage;
 	image_t                 *quarterImage[2];
 	image_t					*calcLevelsImage;
 	image_t					*targetLevelsImage;
@@ -1639,7 +1638,6 @@ typedef struct {
 	FBO_t					*depthFbo;
 	FBO_t					*pshadowFbos[MAX_DRAWN_PSHADOWS];
 	FBO_t					*textureScratchFbo[2];
-	FBO_t					*screenScratchFbo;
 	FBO_t                   *quarterFbo[2];
 	FBO_t					*calcLevelsFbo;
 	FBO_t					*targetLevelsFbo;