[gdm] Revert "gdm-{wayland, x}-session: omit GNOME_SHELL_SESSION_MODE from environment"

[Ray Strode <halfline src gnome org>]

commit 7a5678d7d3dd44ff22b0fe2898b194d2a6f969f0
Author: Ray Strode <rstrode redhat com>
Date:   Mon Aug 14 09:43:28 2017 -0400

    Revert "gdm-{wayland,x}-session: omit GNOME_SHELL_SESSION_MODE from environment"
    
    This reverts commit 9bd3c5f04efc0da7de9fc27237244e22942ef720.
    
    It breaks the greeter and initial-setup.

 daemon/gdm-wayland-session.c |    1 -
 daemon/gdm-x-session.c       |    2 --
 2 files changed, 0 insertions(+), 3 deletions(-)
---
diff --git a/daemon/gdm-wayland-session.c b/daemon/gdm-wayland-session.c
index 742eb26..efdb34e 100644
--- a/daemon/gdm-wayland-session.c
+++ b/daemon/gdm-wayland-session.c
@@ -324,7 +324,6 @@ spawn_session (State        *state,
         g_subprocess_launcher_unsetenv (launcher, "XAUTHORITY");
         g_subprocess_launcher_unsetenv (launcher, "WAYLAND_DISPLAY");
         g_subprocess_launcher_unsetenv (launcher, "WAYLAND_SOCKET");
-        g_subprocess_launcher_unsetenv (launcher, "GNOME_SHELL_SESSION_MODE");
 
         subprocess = g_subprocess_launcher_spawnv (launcher,
                                                    (const char * const *) argv,
diff --git a/daemon/gdm-x-session.c b/daemon/gdm-x-session.c
index 3ac4861..b919e6e 100644
--- a/daemon/gdm-x-session.c
+++ b/daemon/gdm-x-session.c
@@ -643,8 +643,6 @@ spawn_session (State        *state,
                 g_subprocess_launcher_setenv (launcher, "WINDOWPATH", vt, TRUE);
         }
 
-        g_subprocess_launcher_unsetenv (launcher, "GNOME_SHELL_SESSION_MODE");
-
         if (run_script) {
                 subprocess = g_subprocess_launcher_spawn (launcher,
                                                           &error,