fix typo

Change-Id: Ic00f82ea7bbe570ef30f52b353ba147664d755d7
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 14ead83..35b1224 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -51,7 +51,7 @@
 LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES:=
 LOCAL_PREBUILT_STRIP_COMMENTS:=
 LOCAL_INTERMEDIATE_SOURCES:=
-LOCAL_INTERMEDIATE_SOURCE_DIRS:=
+LOCAL_INTERMEDIATE_SOURCE_DIR:=
 LOCAL_JAVACFLAGS:=
 LOCAL_JAVA_LIBRARIES:=
 LOCAL_NO_STANDARD_LIBRARIES:=