blockchain: move bulletproofs to v8

and set v7 height to 1057027 on testnet (one block earlier)
This is to easily dump current nodes since we're going to change
the v7 rules with this.

src/cryptonote_core/blockchain.cpp

@@ -127,7 +127,8 @@ static const struct {
   { 5, 802660, 0, 1472415036 + 86400*180 }, // add 5 months on testnet to shut the update warning up since there's a large gap to v6
 
   { 6, 971400, 0, 1501709789 },
-  { 7, 1057028, 0, 1512211236 },
+  { 7, 1057027, 0, 1512211236 },
+  { 8, 1057058, 0, 1515967497 },
 };
 static const uint64_t testnet_hard_fork_version_1_till = 624633;
 
@@ -2395,11 +2396,11 @@ bool Blockchain::check_tx_outputs(const transaction& tx, tx_verification_context
     }
   }
 
-  // from v7, allow bulletproofs
-  if (hf_version < 7 || !m_testnet) {
+  // from v8, allow bulletproofs
+  if (hf_version < 8) {
     if (!tx.rct_signatures.p.bulletproofs.empty())
     {
-      MERROR("Bulletproofs are not allowed before v7 or on mainnet");
+      MERROR("Bulletproofs are not allowed before v8");
       tvc.m_invalid_output = true;
       return false;
     }