Add FIXME memo

Change-Id: I2e1e3159c29f13fb1f61f9bdaba3ba357161edbe

@@ -38,6 +38,7 @@ public abstract class AbstractProviderRegistry<P extends Provider, S extends Pro
         S service = createProviderService(provider);
         S service = createProviderService(provider);
         services.put(provider.id(), service);
         services.put(provider.id(), service);
         providers.put(provider.id(), provider);
         providers.put(provider.id(), provider);
+        // FIXME populate scheme look-up
         return service;
         return service;
     }
     }