make qtbase source requirement explicit
make qtbase source requirement explicit

getting rid of QT.<module>.sources references, as they don't go well
with real modularization.

Change-Id: Idfe0327b00be173e2c2a0b4fc4d2c50de7c2dbe8
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@digia.com>

mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools