When autosync to cloud was enabled, the old code would crash,
because it synced to cloud from a signal handler, which executed
the main loop when checking the cloud connection, which deleted
the object which was causing the original signal. Or something
like that. See discussion in #4119.
To avoid such problems, send a signal via a 'QueuedConnection'
from QMLManager to itself. The slot will be called once the
signal handler terminates and the main event loop retakes
control.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
de313bd01a