Fix makefile

Change-Id: I8371cee8f68788329d193bb9e0da052033291c48
diff --git a/mbtk/test/libmbtk_http/Makefile b/mbtk/test/libmbtk_http/Makefile
index ad42a13..e33b144 100755
--- a/mbtk/test/libmbtk_http/Makefile
+++ b/mbtk/test/libmbtk_http/Makefile
@@ -1,5 +1,5 @@
-ROOT = $(shell pwd)/../../..
-include $(ROOT)/mbtk/Make.defines
+BUILD_ROOT = $(shell pwd)/../..
+include $(BUILD_ROOT)/Make.defines
 
 INC_DIR +=