message: Resolve a drop_copy lint warning
diff: @@ -218,7 +218,6 @@ fn cargo_compile_offline_with_cached_git_dep() {
  execs().with_stdout("hello from cached git repo rev2\n"),
  );
  - drop(
  File::create(&p.root().join("Cargo.toml"))
  .unwrap()
  .write_all(&format!(
  @@ -234,8 +233,7 @@ fn cargo_compile_offline_with_cached_git_dep() {
  git_project.url(),
  rev1
  ).as_bytes())
  - .unwrap(),
  - );
  + .unwrap();
  let _out = p
  .cargo("build")
  