message: trivial: remove unused variable
  Remove the unused variable "blockTmp" in CMerkleTx::SetMerkleBranch.  It
  was previously used to read the block from disk if not provided as
  argument, but is no longer needed.
diff: @@ -3834,8 +3834,6 @@ CWalletKey::CWalletKey(int64_t nExpires)
  void CMerkleTx::SetMerkleBranch(const CBlockIndex* pindex, int posInBlock)
  {
  - CBlock blockTmp;
  -
  // Update the tx's hashBlock
  hashBlock = pindex->GetBlockHash();
  