Environment variables changes are not propagated to the system.

Note: we already used the Unicode version of the function call,
though without passing the right LPARAM. Might fix the issue...

Task-number: QTIFW-391

Change-Id: I28e0afd45ea7e4d1b904dcf8357fc990dec6767a
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>