#481 [lxsession] 0.5.0 lxsession-logout: Fix user switch with LightDM when GDM is installed.

[Balló György]

Currently if the configured display manager is LightDM, but both GDM and LightDM are installed, the user switch fails, because the default gdmflexiserver is incompatible with LightDM. This patch fixes the problem by removing the duplicated lightdm+gdmflexiserver combination.

[gilir]

Thanks. The fix is correct, but the real reason is that gdmflexiserver is not available anymore with lightdm. So, removing the support is the correct way.