displaymanager: Remove lightdm gdmflexiserver hack.

Remove the hack that symlinks /usr/lib/lightdm/lightdm/gdmflexiserver as
/usr/bin/gdmflexiserver.

Upstream LightDM removed their gdmflexiserver implementation in 1.9.4 in
2013:
http://bazaar.launchpad.net/~lightdm-team/lightdm/trunk/revision/1841

In addition, LightDM was already adding the path containing its
gdmflexiserver implementation to PATH, so there was no use symlinking it
into /usr/bin, potentially overwriting the original version from GDM.
This must have been a workaround for an ancient LightDM version that
didn't even do that.

And finally, the hardcoded /usr/lib/lightdm/lightdm/gdmflexiserver path
was wrong on Fedora to begin with (we had used
/usr/libexec/lightdm/gdmflexiserver, but now the file is completely gone
because upstream removed it).

src/modules/displaymanager/main.py

@@ -238,9 +238,6 @@ def run():
             if default_desktop_environment != None:
                 os.system(
                     "sed -i -e 's/^.*user-session=.*/user-session=%s/' %s/etc/lightdm/lightdm.conf" % (default_desktop_environment.desktop_file, root_mount_point))
-            libcalamares.utils.chroot_call(['ln', '-s',
-                                            '/usr/lib/lightdm/lightdm/gdmflexiserver',
-                                            '/usr/bin/gdmflexiserver'])
             libcalamares.utils.chroot_call(
                 ['chmod', '+r' '/etc/lightdm/lightdm.conf'])
         else: