QMakeProjectManager: Remove unused member
QMakeProjectManager: Remove unused member

Change-Id: I30ae181a3d8c36fd0c0f5c1c0d399fb3fbcd3db4
Reviewed-by: Daniel Teske <d8a411aec9a206efedb4d45b75fe8d13f1e2b628@theqtcompany.com>

xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator