Debugger: Fix warning about unused variable
Debugger: Fix warning about unused variable

Core::mainWindow() is now a static function.

Change-Id: I8da4b72fc47f30fc20a3a2db725d13760a095814
Reviewed-by: Friedemann Kleint <1b9f2592239daaec4856ccc1cfb4d2d55b35fb71@nokia.com>

martyone/sailfish-qtcreator,AltarBeastiful/qt-creator,xianian/qt-creator,Distrotech/qtcreator,duythanhphan/qt-creator,richardmg/qtcreator,malikcjm/qtcreator,darksylinc/qt-creator,jonnor/qt-creator,martyone/sailfish-qtcreator,richardmg/qtcreator,xianian/qt-creator,farseerri/git_code,richardmg/qtcreator,darksylinc/qt-creator,colede/qtcreator,duythanhphan/qt-creator,syntheticpp/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,omniacreator/qtcreator,duythanhphan/qt-creator,martyone/sailfish-qtcreator,jonnor/qt-creator,kuba1/qtcreator,omniacreator/qtcreator,martyone/sailfish-qtcreator,Distrotech/qtcreator,farseerri/git_code,omniacreator/qtcreator,maui-packages/qt-creator,danimo/qt-creator,xianian/qt-creator,malikcjm/qtcreator,darksylinc/qt-creator,AltarBeastiful/qt-creator,AltarBeastiful/qt-creator,jonnor/qt-creator,KDE/android-qt-creator,danimo/qt-creator,Distrotech/qtcreator,colede/qtcreator,danimo/qt-creator,malikcjm/qtcreator,kuba1/qtcreator,colede/qtcreator,malikcjm/qtcreator,amyvmiwei/qt-creator,darksylinc/qt-creator,darksylinc/qt-creator,darksylinc/qt-creator,richardmg/qtcreator,xianian/qt-creator,duythanhphan/qt-creator,KDE/android-qt-creator,amyvmiwei/qt-creator,duythanhphan/qt-creator,malikcjm/qtcreator,xianian/qt-creator,kuba1/qtcreator,amyvmiwei/qt-creator,syntheticpp/qt-creator,farseerri/git_code,KDE/android-qt-creator,martyone/sailfish-qtcreator,maui-packages/qt-creator,omniacreator/qtcreator,Distrotech/qtcreator,KDE/android-qt-creator,duythanhphan/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,maui-packages/qt-creator,jonnor/qt-creator,xianian/qt-creator,darksylinc/qt-creator,darksylinc/qt-creator,AltarBeastiful/qt-creator,KDE/android-qt-creator,syntheticpp/qt-creator,maui-packages/qt-creator,farseerri/git_code,kuba1/qtcreator,richardmg/qtcreator,jonnor/qt-creator,colede/qtcreator,malikcjm/qtcreator,danimo/qt-creator,syntheticpp/qt-creator,danimo/qt-creator,omniacreator/qtcreator,colede/qtcreator,danimo/qt-creator,maui-packages/qt-creator,AltarBeastiful/qt-creator,kuba1/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,syntheticpp/qt-creator,KDE/android-qt-creator,jonnor/qt-creator,omniacreator/qtcreator,amyvmiwei/qt-creator,duythanhphan/qt-creator,amyvmiwei/qt-creator,syntheticpp/qt-creator,maui-packages/qt-creator,farseerri/git_code,danimo/qt-creator,danimo/qt-creator,farseerri/git_code,Distrotech/qtcreator,richardmg/qtcreator,AltarBeastiful/qt-creator,farseerri/git_code,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,colede/qtcreator,omniacreator/qtcreator,colede/qtcreator,richardmg/qtcreator,KDE/android-qt-creator,kuba1/qtcreator,Distrotech/qtcreator,maui-packages/qt-creator,danimo/qt-creator,kuba1/qtcreator,KDE/android-qt-creator,amyvmiwei/qt-creator,malikcjm/qtcreator,AltarBeastiful/qt-creator,syntheticpp/qt-creator,farseerri/git_code,amyvmiwei/qt-creator,Distrotech/qtcreator,kuba1/qtcreator,xianian/qt-creator