message: Fix accumulator smart contract in delegator example
diff: #![cfg_attr(not(feature = "std"), no_std)]
  -#[cfg(not(feature = "ink-as-dependency"))]
  -use ink_core::storage;
  -
  use ink_lang as ink;
  #[ink::contract(version = "0.1.0")]
  mod accumulator {
  + #[cfg(not(feature = "ink-as-dependency"))]
  + use ink_core::storage;
  +
  /// Holds a simple i32 value that can be incremented and decremented.
  #[ink(storage)]
  struct Accumulator {
  