cryptonote: Fix enum check in expand_transaction_2

This was noticed because GCC warned about using an enum value in a
boolean context.

src/cryptonote_core/blockchain.cpp

@@ -2494,7 +2494,7 @@ bool Blockchain::expand_transaction_2(transaction &tx, const crypto::hash &tx_pr
     for (size_t n = 0; n < tx.vin.size(); ++n)
       rv.p.MGs[0].II[n] = rct::ki2rct(boost::get<txin_to_key>(tx.vin[n]).k_image);
   }
-  else if (rv.type == rct::RCTTypeSimple || rv.type == rct::RCTTypeBulletproof || rct::RCTTypeBulletproof2)
+  else if (rv.type == rct::RCTTypeSimple || rv.type == rct::RCTTypeBulletproof || rv.type == rct::RCTTypeBulletproof2)
   {
     CHECK_AND_ASSERT_MES(rv.p.MGs.size() == tx.vin.size(), false, "Bad MGs size");
     for (size_t n = 0; n < tx.vin.size(); ++n)