Remove ChainParams::DefaultMinerThreads

No longer relevant after #5957. This hack existed because of another
hack where the numthreads parameter, on regtest, doubled as how many
blocks to generate.

src/chainparams.cpp

@@ -50,7 +50,6 @@ public:
         pchMessageStart[3] = 0xd9;
         vAlertPubKey = ParseHex("04fc9702847840aaf195de8442ebecedf5b095cdbb9bc716bda9110971b28a49e0ead8564ff0db22209e0374782c093bb899692d524e9d6a6956e7c5ecbcd68284");
         nDefaultPort = 8333;
-        nMinerThreads = 0;
         nPruneAfterHeight = 100000;
 
         /**
@@ -147,7 +146,6 @@ public:
         pchMessageStart[3] = 0x07;
         vAlertPubKey = ParseHex("04302390343f91cc401d56d68b123028bf52e5fca1939df127f63c6467cdf9c8e2c14b61104cf817d0b780da337893ecc4aaff1309e536162dabbdb45200ca2b0a");
         nDefaultPort = 18333;
-        nMinerThreads = 0;
         nPruneAfterHeight = 1000;
 
         //! Modify the testnet genesis block so the timestamp is valid for a later start.
@@ -206,7 +204,6 @@ public:
         pchMessageStart[1] = 0xbf;
         pchMessageStart[2] = 0xb5;
         pchMessageStart[3] = 0xda;
-        nMinerThreads = 1;
         genesis.nTime = 1296688602;
         genesis.nBits = 0x207fffff;
         genesis.nNonce = 2;

src/chainparams.h

@@ -50,8 +50,6 @@ public:
     const std::vector<unsigned char>& AlertKey() const { return vAlertPubKey; }
     int GetDefaultPort() const { return nDefaultPort; }
 
-    /** Used if GenerateBitcoins is called with a negative number of threads */
-    int DefaultMinerThreads() const { return nMinerThreads; }
     const CBlock& GenesisBlock() const { return genesis; }
     bool RequireRPCPassword() const { return fRequireRPCPassword; }
     /** Make miner wait to have peers to avoid wasting work */
@@ -79,7 +77,6 @@ protected:
     //! Raw pub key bytes for the broadcast alert signing key.
     std::vector<unsigned char> vAlertPubKey;
     int nDefaultPort;
-    int nMinerThreads;
     uint64_t nPruneAfterHeight;
     std::vector<CDNSSeedData> vSeeds;
     std::vector<unsigned char> base58Prefixes[MAX_BASE58_TYPES];

src/miner.cpp

@@ -541,13 +541,8 @@ void GenerateBitcoins(bool fGenerate, int nThreads, const CChainParams& chainpar
 {
     static boost::thread_group* minerThreads = NULL;
 
-    if (nThreads < 0) {
-        // In regtest threads defaults to 1
-        if (Params().DefaultMinerThreads())
-            nThreads = Params().DefaultMinerThreads();
-        else
-            nThreads = GetNumCores();
-    }
+    if (nThreads < 0)
+        nThreads = GetNumCores();
 
     if (minerThreads != NULL)
     {