BlockchainDB: Remove txs in reverse order

Data should be removed in the reverse order it was added. Not doing so
breaks assumptions and can cause problems in other DB implementations.

This matches the order of tx removal in
blockchain_storage::purge_block_data_from_blockchain.

src/blockchain_db/blockchain_db.cpp

@@ -26,6 +26,8 @@
 // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#include <boost/range/adaptor/reversed.hpp>
+
 #include "blockchain_db.h"
 #include "cryptonote_core/cryptonote_format_utils.h"
 #include "profile_tools.h"
@@ -133,13 +135,13 @@ void BlockchainDB::pop_block(block& blk, std::vector<transaction>& txs)
   blk = get_top_block();
 
   remove_block();
-  
-  remove_transaction(get_transaction_hash(blk.miner_tx));
-  for (const auto& h : blk.tx_hashes)
+
+  for (const auto& h : boost::adaptors::reverse(blk.tx_hashes))
   {
     txs.push_back(get_tx(h));
     remove_transaction(h);
   }
+  remove_transaction(get_transaction_hash(blk.miner_tx));
 }
 
 bool BlockchainDB::is_open() const