More fixes for Info schema.

lib/pleroma/plugs/user_enabled_plug.ex

lib/pleroma/user.ex

lib/pleroma/user/info.ex

lib/pleroma/web/salmon/salmon.ex

test/plugs/user_enabled_plug_test.exs

test/user_test.exs

test/web/ostatus/ostatus_test.exs

test/web/twitter_api/twitter_api_controller_test.exs