refactor(Core): apply clang-tidy modernize-use-equals-default (#3834)

src/common/Database/DatabaseWorkerPool.h

@@ -38,7 +38,7 @@ public:
     /* Activity state */
     DatabaseWorkerPool();
 
-    ~DatabaseWorkerPool() { }
+    ~DatabaseWorkerPool() = default;
 
     bool Open(const std::string& infoString, uint8 async_threads, uint8 synch_threads);
 

src/common/Database/MySQLConnection.h

@@ -27,7 +27,7 @@ enum ConnectionFlags
 
 struct MySQLConnectionInfo
 {
-    MySQLConnectionInfo() { }
+    MySQLConnectionInfo() = default;
     MySQLConnectionInfo(const std::string& infoString)
     {
         Tokenizer tokens(infoString, ';');

src/common/Database/QueryHolder.h

@@ -16,7 +16,7 @@ private:
     typedef std::pair<SQLElementData, SQLResultSetUnion> SQLResultPair;
     std::vector<SQLResultPair> m_queries;
 public:
-    SQLQueryHolder() { }
+    SQLQueryHolder() = default;
     ~SQLQueryHolder();
     bool SetQuery(size_t index, const char* sql);
     bool SetPQuery(size_t index, const char* format, ...) ATTR_PRINTF(3, 4);

src/common/Database/Transaction.h

@@ -49,7 +49,7 @@ class TransactionTask : public SQLOperation
 
 public:
     TransactionTask(SQLTransaction trans) : m_trans(trans) { } ;
-    ~TransactionTask() override { };
+    ~TransactionTask() override = default;
 
 protected:
     bool Execute() override;