removed useless app key 'registered' from app.src files

Summary: it's only needed by 'rebar3' and 'systools' which we don't use

Reviewed By: afterdusk

Differential Revision: D89759378

fbshipit-source-id: 2b16e2a16362d5ea551175d5102c5d32a02dfca4

Author: Alexander Shturm

taint_server/src/taint_server.app.src

@@ -17,7 +17,6 @@
     {description,
         "App containing servers for the taint app that need an external dependency. They cannot be part of the taint app, because the taint app needs to compile as a parse transform, which can't have dependencies"},
     {vsn, "0.1.0"},
-    {registered, []},
     {mod, {taint_server_app, []}},
     %% NOTE: Remember to sync changes to `applications` to
     %% the BUCK file in the application's base folder