Description of problem:   mga7 dev0

mageiawelcome fails to run on login. Same problem as bug 21454 but
is different software.

$ /usr/bin/mageiawelcome

(mageiawelcome.py:22219): dbind-WARNING **: 11:36:56.613:
Couldn't connect to accessibility bus: Failed to connect to
socket /tmp/dbus-4LF7EkVzgN: Connection refused
Traceback (most recent call last):
  File "/usr/share/mageiawelcome/webgui.py", line 66, in worker
    R.result = function(*args, **kwargs)
  File "/usr/share/mageiawelcome/webgui.py", line 79, in launch_browser
    browser = implementation.create_browser()
  File "/usr/share/mageiawelcome/webgui.py", line 28, in create_browser
    return WebKit.WebView()
  File "/usr/lib64/python3.6/site-packages/gi/module.py", line 215, in __getattr__
    wrapper = metaclass(name, bases, dict_)
TypeError: metaclass conflict: the metaclass of a derived class must be 
a (non-strict) subclass of the metaclasses of all its bases

$ cat /etc/sysconfig/desktop
DISPLAYMANAGER=lightdm

$ env | grep -i desk
DESKTOP_SESSION=xfce
XDG_SESSION_DESKTOP=xfce
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
XDG_CURRENT_DESKTOP=XFCE
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session3

Version-Release number of selected component (if applicable):

How reproducible: Always

Steps to Reproduce:
1. clean install of Mageia-Cauldron-netinstall-nonfree-x86_64.iso  created 2018-09-05 20:01:00 -0500
2. Enable nonfree and tainted media and disable all update selections
3. Pick Custom package install
4. in Package Group Selection screen, set all package groups selected except
   Other Graphical Desktops. In that one select GNOME, Plasma, Xfce

5. After reboot, cauldron bubble graphic goes black with a line of text, hit
   Ctrl+Alt+F2

6. login as root and run the following bug 22620 and bug 22593 workarounds:
   Paste the following at the command line prompt

    systemctl --quiet is-enabled getty@tty1.service 2> /dev/null

   _serv=lightdm
    echo "DISPLAYMANAGER=$_serv" > /etc/sysconfig/desktop
    systemctl disable display-manager.service
    systemctl enable $_serv.service
    systemctl set-default graphical.target

    reboot

7. log into the user account, click up a terminal and run
    /usr/bin/mageiawelcome