Rename config.json to aos_config.json

Plenty of other things are called config.json, so let's pick a more
unique name.

Change-Id: I6510a172ec62674dd1b11bd71cef9aac2480c612
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/y2018/joystick_reader.cc b/y2018/joystick_reader.cc
index 3a5ed63..be7be1f 100644
--- a/y2018/joystick_reader.cc
+++ b/y2018/joystick_reader.cc
@@ -394,7 +394,7 @@
   ::aos::InitGoogle(&argc, &argv);
 
   aos::FlatbufferDetachedBuffer<aos::Configuration> config =
-      aos::configuration::ReadConfig("config.json");
+      aos::configuration::ReadConfig("aos_config.json");
 
   ::aos::ShmEventLoop event_loop(&config.message());
   ::y2018::input::joysticks::Reader reader(&event_loop);