Core/Misc: Multiple static analysis issues fixed (small optimizations and clear code)

src/server/shared/Database/MySQLConnection.cpp

@@ -57,8 +57,7 @@ m_connectionFlags(CONNECTION_ASYNC)
 
 MySQLConnection::~MySQLConnection()
 {
-    if (m_worker)
-        delete m_worker;
+    delete m_worker;
 
     for (size_t i = 0; i < m_stmts.size(); ++i)
         delete m_stmts[i];