Fix FolderListModel versioning

Task-number: QTBUG-34448
Change-Id: Idebfdc123a7b908988c9ae86d7db4831ad0e4433
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Fill recursive ShaderEffectSource with transparent when using alpha.

The logic relies on m_fbo being 0 on the first render pass, in which
case it will pick texture id 0 which is solid black. Though this
works ok, it results in recursive shader effect sources starting
out black which is ugly.

Change-Id: I22b1d50e02c00583837b8152c5fb850263038a93
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>