Avoid a crash in testcalendar
Avoid a crash in testcalendar

When changing between months, we can get into a situation like
'February 30", which GDate doesn't accept. Don't crash in that
case.

grubersjoe/adwaita,grubersjoe/adwaita,jigpu/gtk,jadahl/gtk,Lyude/gtk-,alexlarsson/gtk,Adamovskiy/gtk,davidgumberg/gtk,grubersjoe/adwaita,chergert/gtk,davidgumberg/gtk,jigpu/gtk,ahodesuka/gtk,Lyude/gtk-,grubersjoe/adwaita,ahodesuka/gtk,Lyude/gtk-,jadahl/gtk,grubersjoe/adwaita,davidgumberg/gtk,ahodesuka/gtk,Adamovskiy/gtk,ahodesuka/gtk,Lyude/gtk-,ahodesuka/gtk,ahodesuka/gtk,chergert/gtk,alexlarsson/gtk,jadahl/gtk,davidgumberg/gtk,alexlarsson/gtk,jigpu/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,chergert/gtk,jadahl/gtk,alexlarsson/gtk,jigpu/gtk,Lyude/gtk-,Adamovskiy/gtk,jadahl/gtk,Adamovskiy/gtk,jadahl/gtk,alexlarsson/gtk,ahodesuka/gtk,jigpu/gtk,ahodesuka/gtk,davidgumberg/gtk,chergert/gtk,Adamovskiy/gtk,alexlarsson/gtk,alexlarsson/gtk,davidgumberg/gtk,jigpu/gtk,davidgumberg/gtk,Lyude/gtk-,davidgumberg/gtk,Adamovskiy/gtk,alexlarsson/gtk,Adamovskiy/gtk,grubersjoe/adwaita,grubersjoe/adwaita,Lyude/gtk-,grubersjoe/adwaita,chergert/gtk,jigpu/gtk,jigpu/gtk,Lyude/gtk-,Adamovskiy/gtk