Remove local "debug" variable in Executor.
Remove local "debug" variable in Executor.

We have a canonical way to check whether to print debug messages.

Change-Id: I922559517b138bc31f55034529fe10ff35a9500e
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@digia.com>

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