Allow per module RTTI setting.  This fixes a bug in previous check-ins.

Change-Id: I5fcac192a7945720fd7667f7497078d310370bc5
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index ab6efd4..bc085f5 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -42,6 +42,7 @@
 LOCAL_ASFLAGS:=
 LOCAL_CFLAGS:=
 LOCAL_CPPFLAGS:=
+LOCAL_RTTI_FLAG:=
 LOCAL_C_INCLUDES:=
 LOCAL_LDFLAGS:=
 LOCAL_LDLIBS:=