Running Qt application doesn't change its time zone when the system time zone is changed

The time zone for QDateTime::toLocalTime() does not get updated (to match the system time zone) if the system clock's time zone is changed while the application is running.

Steps to reproduce

• Run the attached sample on Windows 7
• Change System Time Zone (System Date and Time Settings)
• EXPECTED: The time zone change is updated in the sample application
• ACTUAL: No effect in the sample application