Address unload order issues for res_stasis* modules

I've noticed when doing a graceful shutdown that the res_stasis_http.so
module gets unloaded before the modules that use it, which causes some
asserts during their unload.

While r386928 was a quick hack to get it to not assert and die, this
patch increases the use counts on res_stasis.so and res_stasis_http.so
properly. It's a bigger change than I expected, hence the review instead
of just committing it.

Review: https://reviewboard.asterisk.org/r/2489/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@388350 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_stasis.c

@@ -942,6 +942,16 @@ static void sub_varset_handler(void *data,
 	generic_blob_handler(obj, handle_blob_varset);
 }
 
+void stasis_app_ref(void)
+{
+	ast_module_ref(ast_module_info->self);
+}
+
+void stasis_app_unref(void)
+{
+	ast_module_unref(ast_module_info->self);
+}
+
 static int load_module(void)
 {
 	int r = 0;