Remove more unused code

Author: josevalim

lib/ecto/adapters/myxql/connection.ex

@@ -1069,7 +1069,6 @@ if Code.ensure_loaded?(MyXQL) do
     defp ecto_to_db(:naive_datetime, _query),      do: "datetime"
     defp ecto_to_db(:naive_datetime_usec, _query), do: "datetime"
     defp ecto_to_db(atom, _query) when is_atom(atom),  do: Atom.to_string(atom)
-    defp ecto_to_db(str, _query)  when is_binary(str), do: str
     defp ecto_to_db(type, _query) do
       raise ArgumentError,
             "unsupported type `#{inspect(type)}`. The type can either be an atom, a string " <>

test/ecto/adapters/myxql_test.exs

@@ -1018,8 +1018,8 @@ defmodule Ecto.Adapters.MyXQLTest do
                 {:add, :token, :binary, [size: 20, null: false]},
                 {:add, :price, :numeric, [precision: 8, scale: 2, default: {:fragment, "expr"}]},
                 {:add, :on_hand, :integer, [default: 0, null: true]},
-                {:add, :likes, "smallint unsigned", [default: 0, null: false]},
-                {:add, :published_at, "datetime(6)", [null: true]},
+                {:add, :likes, :"smallint unsigned", [default: 0, null: false]},
+                {:add, :published_at, :"datetime(6)", [null: true]},
                 {:add, :is_active, :boolean, [default: true]}]}
 
     assert execute_ddl(create) == ["""