QDBusConnection::connect() behaves like QObject::connect with a
connection type of Qt::UniqueConnection | Qt::QueuedConnection. So
return false if it's already connected.
[ChangeLog][QtDBus][QDBusConnection] Fixed a bug that would cause
QDBusConnection::connect() to return true if a slot was already
connected to the same D-Bus signal. QtDBus does not support multiple
connections.
Change-Id: I87e17314d8b24ae983b1fffd1453aef5a7c9ad0b
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
6f275a4beb