Remove unused env var

lib/livebook.ex

@@ -186,14 +186,6 @@ defmodule Livebook do
       config :livebook, :apps_path, apps_path
     end
 
-    # TODO: remove in v1.0
-    if System.get_env("LIVEBOOK_APPS_PATH_HUB_ID") do
-      IO.warn(
-        ~s/Ignoring LIVEBOOK_APPS_PATH_HUB_ID, this environment variable is no longer used./,
-        []
-      )
-    end
-
     if apps_path_password = Livebook.Config.password!("LIVEBOOK_APPS_PATH_PASSWORD") do
       config :livebook, :apps_path_password, apps_path_password
     end

lib/livebook/application.ex

@@ -92,7 +92,7 @@ defmodule Livebook.Application do
       clear_env_vars()
       Livebook.Hubs.connect_hubs()
 
-      unless serverless?() do
+      if not serverless?() do
         load_apps_dir()
       end
     end