[gdm] Fix typo highlighted in review of bug #606703.

[Brian Cameron <bcameron src gnome org>]

commit 56c7db0913873bf563d00a282be25af7097359f4
Author: Brian Cameron <Brian Cameron sun com>
Date:   Fri Jan 15 10:43:06 2010 -0600

    Fix typo highlighted in review of bug #606703.

 daemon/gdm-session-worker.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/daemon/gdm-session-worker.c b/daemon/gdm-session-worker.c
index be371ca..346bf80 100644
--- a/daemon/gdm-session-worker.c
+++ b/daemon/gdm-session-worker.c
@@ -1410,7 +1410,7 @@ gdm_session_worker_authenticate_user (GdmSessionWorker *worker,
                  * Do not display a different message for user unknown versus
                  * a failed password for a valid user.
                  */
-                if (error_code = PAM_USER_UNKNOWN) {
+                if (error_code == PAM_USER_UNKNOWN) {
                         error_code = PAM_AUTH_ERR;
                 }