Fix build error

[DO NOT MERGE]

ANDROID_BUILD_TOP wasn't worked as expected.
Added temporary work around for building sl4n.

Change-Id: I2f60e22d51f0780d7e5a88ab7439567bf7cab412
diff --git a/sl4n/Android.mk b/sl4n/Android.mk
index 286453c..bf99596 100644
--- a/sl4n/Android.mk
+++ b/sl4n/Android.mk
@@ -22,7 +22,7 @@
 LOCAL_MODULE := sl4n
 
 LOCAL_C_INCLUDES += \
-  $(ANDROID_BUILD_TOP)/system/bt \
+  $(LOCAL_PATH)/../../../../../system/bt \
   $(LOCAL_PATH)/rapidjson/include \
   $(LOCAL_PATH)/facades