don't punish honest peer on reorg

[auruya]

currently on reorg, if there is missing tx in a block of the alt chain we trying to switch to, we fail to add the block which had the missing tx in our pool and we ban the honest sending peer, although we only failed to verify the block since we dropped its txs from our pool. This PR fixes that by correctly copying the missing_txs flag back to handle_notify_new_fluffy_block where we check whether the missing tx from the last block we are trying to add or from an ancestor block. If its from an ancestor block we re-request the reorg blocks so we get the blocks and their txs completely.

[j-berman]

Looks related to #374

[auruya]

yes @j-berman , also before the fix during a reorg missing txs never requested from peer since missing_txs weren't set to true. So the problem existed even missing txs only existed on the last received alt chain block.