extend error message with product's location
extend error message with product's location

The error "Product 'Foo' depends on 'Bar' but 'Bar' is disabled."
now contains the locations of both products.

Task-number: QBS-694
Change-Id: I2633ee90d9442923bf1630fce81dc106c4e3639e
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@digia.com>

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