Remove duplicated check from CWallet::AvailableCoins

[Duality-CDOO]

  // We should not consider coins which aren't at least in our mempool
  // It's possible for these to be conflicted via ancestors which we may never be able to detect
  if (nDepth == 0 && !pcoin->InMempool())
      continue;

[nmarley]

utACK

Good catch. Looks like we backported bitcoin#7715 from Bitcoin in f933c67 which was already applied in f4e4dd6

[UdjinM6]

👍

utACK