blockchain: forbid older BP rct versions from v11

src/cryptonote_core/blockchain.cpp

@@ -2423,7 +2423,19 @@ bool Blockchain::check_tx_outputs(const transaction& tx, tx_verification_context
     if (tx.version >= 2) {
       if (tx.rct_signatures.type == rct::RCTTypeBulletproof2)
       {
-        MERROR_VER("Bulletproofs v2 are not allowed before v" << HF_VERSION_SMALLER_BP);
+        MERROR_VER("Ringct type " << (unsigned)rct::RCTTypeBulletproof2 << " is not allowed before v" << HF_VERSION_SMALLER_BP);
+        tvc.m_invalid_output = true;
+        return false;
+      }
+    }
+  }
+
+  // from v11, allow only bulletproofs v2
+  if (hf_version > HF_VERSION_SMALLER_BP) {
+    if (tx.version >= 2) {
+      if (tx.rct_signatures.type == rct::RCTTypeBulletproof)
+      {
+        MERROR_VER("Ringct type " << (unsigned)rct::RCTTypeBulletproof << " is not allowed from v" << (HF_VERSION_SMALLER_BP + 1));
         tvc.m_invalid_output = true;
         return false;
       }