Stop monitoring seat changes if uid is set

Technically it would be possible to create UserInfo object in QML before
activation has happened and then set it's uid to another user. In
practice that's quite unusual thing to do. Previously it would have
replaced the user with current user but now it just stops monitoring for
changes instead.

Signed-off-by: Tomi Leppänen <tomi.leppanen@jolla.com>

src/userinfo.cpp

@@ -564,6 +564,11 @@ void UserInfo::waitForActivation()
             auto *notifier = new QSocketNotifier(fd, QSocketNotifier::Read, this);
             connect(notifier, &QSocketNotifier::activated, this, [this, notifier, monitor](int socket) {
                 Q_UNUSED(socket)
+                if (uid() != (int)UnknownCurrentUserId) {
+                    // This user has been changed to someone else already, stop monitoring
+                    qCDebug(lcUsersLog) << "UserInfo uid had been changed";
+                    notifier->deleteLater();
+                }
                 // Check if seat0 has got active user
                 uid_t uid = InvalidId;
                 if (sd_seat_get_active("seat0", NULL, &uid) >= 0 && uid != InvalidId) {