Remove old qt version settings on upgrade.
Remove old qt version settings on upgrade.

Change-Id: I1544c4c241fced2015d2bdfb57a70ce828223786
Reviewed-on: http://codereview.qt.nokia.com/1080
Reviewed-by: Daniel Teske <d8a411aec9a206efedb4d45b75fe8d13f1e2b628@nokia.com>

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