return value cleanup
return value cleanup

functions which have essentially two return values are kinda confusing.
so represent file & parse errors as false in the regular evaluation
result (like qmake effectively does).

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