0024725: AIS_TexturedShape - flag switching texture modulation mode does not work

- Missing code restored
- "vtexture" command improved to support texture modulation option

remarks from kgv

src/AIS/AIS_TexturedShape.cxx

@@ -244,6 +244,11 @@ void AIS_TexturedShape::updateAttributes (const Handle(Prs3d_Presentation)& theP
     return;
   }
 
+  if (myModulate)
+    myTexture->EnableModulate();
+  else
+    myTexture->DisableModulate();
+
   if (myToShowTriangles)
     myAspect->SetEdgeOn();
   else