add assertion in Transformer::setupOutputs
add assertion in Transformer::setupOutputs

We need file tags for every artifact.
Assert, if we encounter an artifact without file tags.

Change-Id: I29b36699b7d8ba4515cd85fcd3cfe819836e9fe4
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@nokia.com>
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@nokia.com>

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