rsync: Move to /system_ext

Change-Id: I13519eb1a9eac36c6e315593986b212f65041ab3
diff --git a/Android.bp b/Android.bp
index f60f289..5279c67 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,6 +1,6 @@
 cc_binary {
     name: "rsync",
-    product_specific: true,
+    system_ext_specific: true,
 
     cflags: ["-DHAVE_CONFIG_H"] + [
         "-Wno-deprecated-declarations",