refactor: took out unused member functions

Took out the following unused member functions:

- 'DBHeightKey()'
- 'GetType()'
- 'operator='

src/index/blockfilterindex.cpp

@@ -51,7 +51,6 @@ struct DBVal {
 struct DBHeightKey {
     int height;
 
-    DBHeightKey() : height(0) {}
     explicit DBHeightKey(int height_in) : height(height_in) {}
 
     template<typename Stream>

src/script/bitcoinconsensus.cpp

@@ -16,8 +16,7 @@ namespace {
 class TxInputStream
 {
 public:
-    TxInputStream(int nTypeIn, int nVersionIn, const unsigned char *txTo, size_t txToLen) :
-    m_type(nTypeIn),
+    TxInputStream(int nVersionIn, const unsigned char *txTo, size_t txToLen) :
     m_version(nVersionIn),
     m_data(txTo),
     m_remaining(txToLen)
@@ -47,9 +46,7 @@ public:
     }
 
     int GetVersion() const { return m_version; }
-    int GetType() const { return m_type; }
 private:
-    const int m_type;
     const int m_version;
     const unsigned char* m_data;
     size_t m_remaining;
@@ -84,7 +81,7 @@ static int verify_script(const unsigned char *scriptPubKey, unsigned int scriptP
         return set_error(err, bitcoinconsensus_ERR_INVALID_FLAGS);
     }
     try {
-        TxInputStream stream(SER_NETWORK, PROTOCOL_VERSION, txTo, txToLen);
+        TxInputStream stream(PROTOCOL_VERSION, txTo, txToLen);
         CTransaction tx(deserialize, stream);
         if (nIn >= tx.vin.size())
             return set_error(err, bitcoinconsensus_ERR_TX_INDEX);

src/test/util_tests.cpp

@@ -1972,12 +1972,6 @@ struct Tracker
         copies = t.copies + 1;
         return *this;
     }
-    Tracker& operator=(Tracker&& t) noexcept
-    {
-        origin = t.origin;
-        copies = t.copies;
-        return *this;
-    }
 };
 
 }