Fix Finder out path in multiproduct_kati

Bug: 64363847
Test: ./build/soong/build_test.bash --dist --keep
Change-Id: I70b08023b94b5789dc8394651bbac4c49c82787f

cmd/multiproduct_kati/main.go

@@ -277,10 +277,9 @@ func main() {
 				Thread:         trace.NewThread(product),
 			}}
 
-			build.FindSources(productCtx, config, finder)
-
 			productConfig := build.NewConfig(productCtx)
 			productConfig.Environment().Set("OUT_DIR", productOutDir)
+			build.FindSources(productCtx, productConfig, finder)
 			productConfig.Lunch(productCtx, product, *buildVariant)
 
 			build.Build(productCtx, productConfig, build.BuildProductConfig)