Fix T43531: Wrong object center-dot color

Write objects center point to the nearest depth.

source/blender/editors/space_view3d/drawobject.c

@@ -740,6 +740,8 @@ static void drawcentercircle(View3D *v3d, RegionView3D *rv3d, const float co[3],
 	/* using gldepthfunc guarantees that it does write z values,
 	 * but not checks for it, so centers remain visible independent order of drawing */
 	if (v3d->zbuf) glDepthFunc(GL_ALWAYS);
+	/* write to near buffer always */
+	glDepthRange(0.0, 0.0);
 	glEnable(GL_BLEND);
 	
 	if (special_color) {
@@ -769,6 +771,7 @@ static void drawcentercircle(View3D *v3d, RegionView3D *rv3d, const float co[3],
 	/* finish up */
 	glDisableClientState(GL_VERTEX_ARRAY);
 
+	glDepthRange(0.0, 1.0);
 	glDisable(GL_BLEND);
 
 	if (v3d->zbuf) glDepthFunc(GL_LEQUAL);