No need to reservekey for sake

src/main.cpp

@@ -3994,8 +3994,6 @@ class TxPriorityCompare
 //   fProofOfStake: try (best effort) to make a proof-of-stake block
 CBlock* CreateNewBlock(CWallet* pwallet, bool fProofOfStake)
 {
-    CReserveKey reservekey(pwallet);
-
     // Create new block
     auto_ptr<CBlock> pblock(new CBlock());
     if (!pblock.get())
@@ -4006,7 +4004,14 @@ CBlock* CreateNewBlock(CWallet* pwallet, bool fProofOfStake)
     txNew.vin.resize(1);
     txNew.vin[0].prevout.SetNull();
     txNew.vout.resize(1);
-    txNew.vout[0].scriptPubKey << reservekey.GetReservedKey() << OP_CHECKSIG;
+
+    if (!fProofOfStake)
+    {
+        CReserveKey reservekey(pwallet);
+        txNew.vout[0].scriptPubKey << reservekey.GetReservedKey() << OP_CHECKSIG;
+    }
+    else
+        txNew.vout[0].SetEmpty();
 
     // Add our coinbase tx as first transaction
     pblock->vtx.push_back(txNew);
@@ -4051,7 +4056,6 @@ CBlock* CreateNewBlock(CWallet* pwallet, bool fProofOfStake)
                 if (txCoinStake.nTime >= max(pindexPrev->GetMedianTimePast()+1, pindexPrev->GetBlockTime() - nMaxClockDrift))
                 {   // make sure coinstake would meet timestamp protocol
                     // as it would be the same as the block timestamp
-                    pblock->vtx[0].vout[0].SetEmpty();
                     pblock->vtx[0].nTime = txCoinStake.nTime;
                     pblock->vtx.push_back(txCoinStake);
                 }