message: Remove unused pwalletdb from CommitTransaction
  Coming from btc@5723bb44ce2c6bb14114aa7f211160702a47ac91
diff: @@ -2947,11 +2947,6 @@ CWallet::CommitResult CWallet::CommitTransaction(CWalletTx& wtxNew, CReserveKey&
  LOCK2(cs_main, cs_wallet);
  LogPrintf("%s:\n%s", __func__, wtxNew.ToString());
  {
  - // This is only to keep the database open to defeat the auto-flush for the
  - // duration of this scope. This is the only place where this optimization
  - // maybe makes sense; please don't do it anywhere else.
  - CWalletDB* pwalletdb = fFileBacked ? new CWalletDB(strWalletFile, "r+") : NULL;
  -
  // Take key pair from key pool so it won't be used again
  reservekey.KeepKey();
  @@ -2972,9 +2967,6 @@ CWallet::CommitResult CWallet::CommitTransaction(CWalletTx& wtxNew, CReserveKey&
  updated_hashes.insert(txin.prevout.hash);
  }
  }
  -
  - if (fFileBacked)
  - delete pwalletdb;
  }
  res.hashTx = wtxNew.GetHash();
  