QtCreator: Remove separate d3dcompiler download

D3DCompiler_43.dll is already part of the qt-creator 7z

Change-Id: Ibe0f4247c013c59d176efb6c17272840e470b362
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>