[ksmserver] Do not try to start X11 window manager if Wayland env variables are set
Review Request #123444 - Created April 21, 2015 and submitted
If ksmserver is started in a session with WAYLAND_DISPLAY and/or WAYLAND_SOCKET being exported we can assume that the Xserver is an Xwayland server. In that case the wayland compositor is also the window maager. Thus starting a window manager would either fail or create severe havoc in case it succeeds in replacing the running window manager.