support submodule syntax in platform config files
support submodule syntax in platform config files

Change-Id: I77c36a3a09c15765a7f3ff74945b27196ad481a9
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@nokia.com>

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