fix Windows SDK lookup for x86_64 build
fix Windows SDK lookup for x86_64 build

64 bit builds of qbs must look in the Wow3264 registry tree.
We already did that for VS but not for the SDKs.

Change-Id: If96b7d184816c20b7075c5392bc1fdbb45d6f01d
Reviewed-by: Jake Petroules <2d627e1cecd5435752fa500bacbe05f7cc90c369@petroules.com>
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@digia.com>

qtproject/qt-labs-qbs,qt-labs/qbs,Distrotech/qbs,Distrotech/qbs,Distrotech/qbs,villytiger/qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs,Distrotech/qbs,Distrotech/qbs,qt-labs/qbs,qt-labs/qbs,villytiger/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,villytiger/qbs,Distrotech/qbs,gatzka/qt-labs-qbs,villytiger/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,villytiger/qbs,gatzka/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,villytiger/qbs,Distrotech/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs