Add ABFS (Android Build Filesystem) configuration option to Soong

Change-Id: Ibbe81004adc67b1212d7e619a35f7425bfee0d72
diff --git a/ui/build/dumpvars.go b/ui/build/dumpvars.go
index e77df44..5df3a95 100644
--- a/ui/build/dumpvars.go
+++ b/ui/build/dumpvars.go
@@ -93,7 +93,7 @@
 	defer tool.Finish()
 
 	cmd := Command(ctx, config, "dumpvars",
-		config.PrebuiltBuildTool("ckati"),
+		config.KatiBin(),
 		"-f", "build/make/core/config.mk",
 		"--color_warnings",
 		"--kati_stats",