Adding app_label to xproto

Change-Id: I153771306783c76278bc776c3938dfe262689e26
(cherry picked from commit 29f02d3f74363b411ebba6c7dde3fbddd29d8975)
diff --git a/xos/exampleservice.xproto b/xos/exampleservice.xproto
index 7356f3a..9b4ea5e 100644
--- a/xos/exampleservice.xproto
+++ b/xos/exampleservice.xproto
@@ -1,4 +1,5 @@
 option name = "exampleservice";
+option app_label = "exampleservice";
 option verbose_name = "Example Service";
 
 message ExampleService (Service){