Remove superfluous migration.

priv/repo/migrations/20190219192317_create_user_mutes.exs

@@ -1,7 +0,0 @@
-defmodule Pleroma.Repo.Migrations.CreateUserMutes do
-  use Ecto.Migration
-
-  def change do
-    execute "UPDATE users SET info = jsonb_set(info, '{mutes}', '[]'::jsonb);"
-  end
-end