Remove submodules

We're now releasing from qt5.git / qt-creator.git

Change-Id: I3ae36d9ea64826a0eaff9ba4f8d269e11faa9ce1
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>