Fix abi of Windows SDK 7.0

Microsoft likes to name SDKs strangely. So Windows SDK 7.0 is using the
msvc 2008 compiler, Windows SDK 7.0A is bundled with msvc 2010 and
Windows SDK 7.1 actually contains a msvc 2010 compiler.

I have tested that by installing all 3 SDKS.

Task-number: QTCREATORBUG-8831

Change-Id: Iaee4e6312caf874da9584512bd72cc0617c3166b
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Reviewed-by: David Schulz <david.schulz@digia.com>