Cursor.cpp: fix warning

Source/Urho3D/UI/Cursor.cpp

@@ -92,12 +92,12 @@ void Cursor::RegisterObject(Context* context)
 
 void Cursor::GetBatches(Vector<UIBatch>& batches, Vector<float>& vertexData, const IntRect& currentScissor)
 {
-    unsigned initialSize = vertexData.Size();
+    i32 initialSize = vertexData.Size();
     const IntVector2& offset = shapeInfos_[shape_].hotSpot_;
     Vector2 floatOffset(-(float)offset.x_, -(float)offset.y_);
-
     BorderImage::GetBatches(batches, vertexData, currentScissor);
-    for (unsigned i = initialSize; i < vertexData.Size(); i += 6)
+
+    for (i32 i = initialSize; i < vertexData.Size(); i += 6)
     {
         vertexData[i] += floatOffset.x_;
         vertexData[i + 1] += floatOffset.y_;