[wallet] Add logging to MarkReserveKeysAsUsed

src/wallet/wallet.cpp

@@ -3659,6 +3659,7 @@ void CWallet::MarkReserveKeysAsUsed(int64_t keypool_id)
             m_pool_key_to_index.erase(keypool.vchPubKey.GetID());
         }
         walletdb.ErasePool(index);
+        LogPrintf("keypool index %d removed\n", index);
         it = setKeyPool->erase(it);
     }
 }