repair products with artifacts that are not generated by rules
repair products with artifacts that are not generated by rules

Having a product with a Transformer that generates artifacts but
without any valid rules could not be handled anymore.

Change-Id: I37074d525bd4074b0e423eed8e4250d51fd40d85
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@nokia.com>

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