Context behaviour subtly changed in Qt5.14 which has exposed some
questionable things in this KCM.
Auorae::Decoration is a context property of the loaded QML.
QObject::~QObject signals it's own deletion before deleting children.
This means the bindings of loaded QML update in particular
aurorae.qml
DecorationOptions {
id: options
deco: decoration
}DecorationOptions has a pointer to the previously set decoration which
is now dangling, and we crash.
Rather than adding more guards and smart pointers in DecorationOptions,
this patch deletes the QQmlContext before deleting the context
properties that we expose.
It also moves unreferring the shared qmlcontext we inherit from till
after we've deleted the child context, because it didn't make sense.