Depend on config rule instead of file.

The aos_config rule used to require you to depend on {name}.json to get
the output.  That was weird and hid private/testonly/etc.  Instead,
depend on the rule directly.

Change-Id: I1596a6c1f44b246a0db1bbc562468530a0b69614
diff --git a/frc971/codelab/BUILD b/frc971/codelab/BUILD
index ac0b80c..ddc5466 100644
--- a/frc971/codelab/BUILD
+++ b/frc971/codelab/BUILD
@@ -7,7 +7,7 @@
     name = "basic_test",
     testonly = 1,
     srcs = ["basic_test.cc"],
-    data = [":config.json"],
+    data = [":config"],
     deps = [
         ":basic",
         ":basic_goal_fbs",