Fix output problem in toolchain detector.
Fix output problem in toolchain detector.

QString::arg() was missing.

Change-Id: I3c9f139dfdc7547cf1dc137388e656a45179a23a
Reviewed-by: hjk <6fac1c92f5b9c7890a04d7f8a9d8912d16355eac@ovi.com>

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