Fix clean-oat

Change-Id: I96ba59794e50f630aaa06d226b1048000b1b6188
diff --git a/Android.mk b/Android.mk
index bf2eb9a..76fb411 100644
--- a/Android.mk
+++ b/Android.mk
@@ -18,6 +18,7 @@
 
 art_path := $(LOCAL_PATH)
 art_build_path := $(art_path)/build
+include $(art_build_path)/Android.common.mk
 
 ########################################################################
 # clean-oat targets