wallet2: fix stagenet get_approximate_blockchain_height

src/wallet/wallet2.cpp

@@ -13146,7 +13146,7 @@ uint64_t wallet2::get_approximate_blockchain_height() const
   // Calculated blockchain height
   uint64_t approx_blockchain_height = fork_block + (time(NULL) - fork_time)/seconds_per_block;
   // testnet and stagenet got some huge rollbacks, so the estimation is way off
-  static const uint64_t approximate_rolled_back_blocks = m_nettype == TESTNET ? 342100 : 30000;
+  static const uint64_t approximate_rolled_back_blocks = m_nettype == TESTNET ? 342100 : m_nettype == STAGENET ? 60000 : 30000;
   if ((m_nettype == TESTNET || m_nettype == STAGENET) && approx_blockchain_height > approximate_rolled_back_blocks)
     approx_blockchain_height -= approximate_rolled_back_blocks;
   LOG_PRINT_L2("Calculated blockchain height: " << approx_blockchain_height);