Improve examples/var_service READMEs

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/examples/var_service/fw/README b/examples/var_service/fw/README
new file mode 100644
index 0000000..4ddccb2
--- /dev/null
+++ b/examples/var_service/fw/README
@@ -0,0 +1,5 @@
+The real README file is one directory up.
+
+This directory's run script can have useful comments.
+If it doesn't but you feel it should, please send a patch
+to busybox's mailing list.