Fix resolve_file_name called twice to the same file (#1)

Hello! Thank you for your library.

We identified a bug where the resolve_file_name is called twice to the
same file.

If we a resolve file name function like suggested in the docs:

    file_name = Path.basename(file.file_name, Path.extname(file.file_name))

    "#{version}_#{file_name}"

If that function is called twice for the same file, instead of having "thumb_filename.jpg",
we end having "thumb_thumb_filename.jpg".

The resolve_file_name is called first in the abstract logic:
https://github.com/elixir-waffle/waffle/blob/c781d5a7e7058d297783669ad1a830bd8928c73d/lib/waffle/actions/store.ex#L134

Then again here. The code change I'm proposing basically imitates the AWS adapter
that just call file.file_name:

https://github.com/elixir-waffle/waffle/blob/c781d5a7e7058d297783669ad1a830bd8928c73d/lib/waffle/storage/s3.ex#L144

lib/waffle/storage/google/cloud_storage.ex

@@ -105,18 +105,10 @@ defmodule Waffle.Storage.Google.CloudStorage do
   Returns the full file path for the upload destination.
   """
   @spec path_for(Types.definition(), Types.version(), Types.meta()) :: String.t()
-  def path_for(definition, version, meta) do
+  def path_for(definition, version, meta = {file, _scope}) do
     definition
     |> storage_dir(version, meta)
-    |> Path.join(fullname(definition, version, meta))
-  end
-
-  @doc """
-  A wrapper for `Waffle.Definition.Versioning.resolve_file_name/3`.
-  """
-  @spec fullname(Types.definition(), Types.version(), Types.meta()) :: String.t()
-  def fullname(definition, version, meta) do
-    Waffle.Definition.Versioning.resolve_file_name(definition, version, meta)
+    |> Path.join(file.file_name)
   end
 
   @spec data({Types.file(), String.t()}) :: {:file | :binary, String.t()}

test/waffle/storage/google/cloud_storage_test.exs

@@ -11,12 +11,14 @@ defmodule Waffle.Storage.Google.CloudStorageTest do
 
   def random_name(_) do
     name = 8 |> :crypto.strong_rand_bytes() |> Base.encode16()
-    %{name: name, path: "#{@remote_dir}/#{name}.png"}
+    %{name: "#{name}.png", path: "#{@remote_dir}/#{name}.png"}
   end
 
   def create_wafile(_), do: %{wafile: Waffle.File.new(@file_path, DummyDefinition)}
 
   def setup_waffle(%{wafile: file, name: name}) do
+    file = Map.put(file, :file_name, name)
+
     %{
       definition: DummyDefinition,
       version: :original,
@@ -132,7 +134,7 @@ defmodule Waffle.Storage.Google.CloudStorageTest do
       Application.put_env(:waffle, :asset_host, "cdn-domain.com")
 
       assert CloudStorage.url(def, ver, meta) ==
-               "https://cdn-domain.com/#{@remote_dir}/#{name}.png"
+               "https://cdn-domain.com/#{@remote_dir}/#{name}"
 
       Application.delete_env(:waffle, :asset_host)
     end