Fix leaking a toolchain per QtVersion.
Fix leaking a toolchain per QtVersion.

Reviewed-By: ossi

pcacjr/qt-creator,kuba1/qtcreator,sandsmark/qtcreator-minimap,amyvmiwei/qt-creator,enricoros/k-qt-creator-inspector,KDE/android-qt-creator,AltarBeastiful/qt-creator,pcacjr/qt-creator,ostash/qt-creator-i18n-uk,danimo/qt-creator,pcacjr/qt-creator,azat/qtcreator,duythanhphan/qt-creator,xianian/qt-creator,renatofilho/QtCreator,dmik/qt-creator-os2,Distrotech/qtcreator,KDE/android-qt-creator,colede/qtcreator,duythanhphan/qt-creator,xianian/qt-creator,farseerri/git_code,malikcjm/qtcreator,renatofilho/QtCreator,xianian/qt-creator,hdweiss/qt-creator-visualizer,duythanhphan/qt-creator,AltarBeastiful/qt-creator,malikcjm/qtcreator,richardmg/qtcreator,bakaiadam/collaborative_qt_creator,sandsmark/qtcreator-minimap,hdweiss/qt-creator-visualizer,malikcjm/qtcreator,farseerri/git_code,farseerri/git_code,malikcjm/qtcreator,sandsmark/qtcreator-minimap,omniacreator/qtcreator,hdweiss/qt-creator-visualizer,bakaiadam/collaborative_qt_creator,darksylinc/qt-creator,KDE/android-qt-creator,KDAB/KDAB-Creator,ostash/qt-creator-i18n-uk,dmik/qt-creator-os2,colede/qtcreator,KDE/android-qt-creator,AltarBeastiful/qt-creator,farseerri/git_code,yinyunqiao/qtcreator,kuba1/qtcreator,jonnor/qt-creator,KDAB/KDAB-Creator,KDE/android-qt-creator,AltarBeastiful/qt-creator,ostash/qt-creator-i18n-uk,bakaiadam/collaborative_qt_creator,duythanhphan/qt-creator,darksylinc/qt-creator,azat/qtcreator,syntheticpp/qt-creator,dmik/qt-creator-os2,hdweiss/qt-creator-visualizer,kuba1/qtcreator,omniacreator/qtcreator,danimo/qt-creator,amyvmiwei/qt-creator,maui-packages/qt-creator,amyvmiwei/qt-creator,enricoros/k-qt-creator-inspector,richardmg/qtcreator,syntheticpp/qt-creator,farseerri/git_code,kuba1/qtcreator,ostash/qt-creator-i18n-uk,AltarBeastiful/qt-creator,kuba1/qtcreator,dmik/qt-creator-os2,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,Distrotech/qtcreator,colede/qtcreator,amyvmiwei/qt-creator,colede/qtcreator,enricoros/k-qt-creator-inspector,dmik/qt-creator-os2,hdweiss/qt-creator-visualizer,kuba1/qtcreator,ostash/qt-creator-i18n-uk,azat/qtcreator,colede/qtcreator,yinyunqiao/qtcreator,omniacreator/qtcreator,xianian/qt-creator,duythanhphan/qt-creator,xianian/qt-creator,richardmg/qtcreator,azat/qtcreator,enricoros/k-qt-creator-inspector,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,KDAB/KDAB-Creator,syntheticpp/qt-creator,yinyunqiao/qtcreator,sandsmark/qtcreator-minimap,pcacjr/qt-creator,colede/qtcreator,xianian/qt-creator,Distrotech/qtcreator,Distrotech/qtcreator,jonnor/qt-creator,jonnor/qt-creator,hdweiss/qt-creator-visualizer,danimo/qt-creator,farseerri/git_code,jonnor/qt-creator,Distrotech/qtcreator,KDAB/KDAB-Creator,yinyunqiao/qtcreator,renatofilho/QtCreator,richardmg/qtcreator,darksylinc/qt-creator,xianian/qt-creator,maui-packages/qt-creator,syntheticpp/qt-creator,danimo/qt-creator,danimo/qt-creator,syntheticpp/qt-creator,martyone/sailfish-qtcreator,syntheticpp/qt-creator,kuba1/qtcreator,jonnor/qt-creator,farseerri/git_code,maui-packages/qt-creator,amyvmiwei/qt-creator,jonnor/qt-creator,azat/qtcreator,danimo/qt-creator,AltarBeastiful/qt-creator,duythanhphan/qt-creator,syntheticpp/qt-creator,maui-packages/qt-creator,martyone/sailfish-qtcreator,colede/qtcreator,malikcjm/qtcreator,maui-packages/qt-creator,enricoros/k-qt-creator-inspector,renatofilho/QtCreator,farseerri/git_code,ostash/qt-creator-i18n-uk,omniacreator/qtcreator,KDAB/KDAB-Creator,maui-packages/qt-creator,enricoros/k-qt-creator-inspector,pcacjr/qt-creator,yinyunqiao/qtcreator,martyone/sailfish-qtcreator,omniacreator/qtcreator,bakaiadam/collaborative_qt_creator,darksylinc/qt-creator,bakaiadam/collaborative_qt_creator,duythanhphan/qt-creator,sandsmark/qtcreator-minimap,maui-packages/qt-creator,yinyunqiao/qtcreator,pcacjr/qt-creator,dmik/qt-creator-os2,danimo/qt-creator,KDE/android-qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,darksylinc/qt-creator,amyvmiwei/qt-creator,renatofilho/QtCreator,sandsmark/qtcreator-minimap,danimo/qt-creator,darksylinc/qt-creator,azat/qtcreator,omniacreator/qtcreator,kuba1/qtcreator,Distrotech/qtcreator,xianian/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,renatofilho/QtCreator,pcacjr/qt-creator,yinyunqiao/qtcreator,richardmg/qtcreator,enricoros/k-qt-creator-inspector,omniacreator/qtcreator,richardmg/qtcreator,kuba1/qtcreator,richardmg/qtcreator,darksylinc/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,bakaiadam/collaborative_qt_creator,KDE/android-qt-creator,dmik/qt-creator-os2,malikcjm/qtcreator,ostash/qt-creator-i18n-uk,KDE/android-qt-creator,KDAB/KDAB-Creator,AltarBeastiful/qt-creator,malikcjm/qtcreator,AltarBeastiful/qt-creator,bakaiadam/collaborative_qt_creator,darksylinc/qt-creator