[gnome-control-center] users: Fix resetting the avatar

[Matthias Clasen <matthiasc src gnome org>]

commit b0aecdd9870fa6c1650c46f83a69d5ee4b3693c0
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Nov 25 22:48:23 2012 -0500

    users: Fix resetting the avatar
    
    This probably broke when the D-Bus code was ported to GDBus, as
    passing NULL for a string into a GVariant constructor doesn't work.
    Thankfully, passing an empty string has just the same effect.
    https://bugzilla.gnome.org/show_bug.cgi?id=673841

 panels/user-accounts/um-photo-dialog.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/panels/user-accounts/um-photo-dialog.c b/panels/user-accounts/um-photo-dialog.c
index 6957992..b4fe847 100644
--- a/panels/user-accounts/um-photo-dialog.c
+++ b/panels/user-accounts/um-photo-dialog.c
@@ -247,7 +247,7 @@ static void
 none_icon_selected (GtkMenuItem   *menuitem,
                     UmPhotoDialog *um)
 {
-        um_user_set_icon_file (um->user, NULL);
+        um_user_set_icon_file (um->user, "");
 }
 
 static void