QCborStreamReader::setDevice needs explicit reparse

When setting the device not in the constructor but with setDevice, parsing will fail when reparse is not called. Not sure this qualifies as a bug, but this behavior is not mentioned in the setDevice or reparse documentation.

QProcess p;
p.start("processor");
p.waitForFinished();

QCborStreamReader cbr;
cbr.setDevice(&p);
cbr.reparse(); // parsing will fail without this

// do parsing