wallet2: fix get_approximate_blockchain_height for stagenet

src/wallet/wallet2.cpp

@@ -9145,9 +9145,9 @@ uint64_t wallet2::get_daemon_blockchain_target_height(string &err)
 uint64_t wallet2::get_approximate_blockchain_height() const
 {
   // time of v2 fork
-  const time_t fork_time = m_nettype == TESTNET ? 1448285909 : m_nettype == STAGENET ? (time_t)-1/*TODO*/ : 1458748658;
+  const time_t fork_time = m_nettype == TESTNET ? 1448285909 : m_nettype == STAGENET ? 1520937818 : 1458748658;
   // v2 fork block
-  const uint64_t fork_block = m_nettype == TESTNET ? 624634 : m_nettype == STAGENET ? (uint64_t)-1/*TODO*/ : 1009827;
+  const uint64_t fork_block = m_nettype == TESTNET ? 624634 : m_nettype == STAGENET ? 32000 : 1009827;
   // avg seconds per block
   const int seconds_per_block = DIFFICULTY_TARGET_V2;
   // Calculated blockchain height