Update our copy of xdg-utils to 2010-08-30, and include a patched xdg-mime.

third_party/xdg-utils/scripts/xdg-utils-common.in

Index: third_party/xdg-utils/scripts/xdg-utils-common.in
===================================================================
--- third_party/xdg-utils/scripts/xdg-utils-common.in	(revision 57942)
+++ third_party/xdg-utils/scripts/xdg-utils-common.in	(working copy)
@@ -92,7 +92,7 @@
 }
 
 #------------------------------------------------------------
-# Exit script on insufficient permission to read a specified file
+# Exit script on insufficient permission to write a specified file
 
 exit_failure_file_permission_write()
 {
@@ -195,7 +195,8 @@
 {
     if [ x"$KDE_FULL_SESSION" = x"true" ]; then DE=kde;
     elif [ x"$GNOME_DESKTOP_SESSION_ID" != x"" ]; then DE=gnome;
-    elif xprop -root _DT_SAVE_MODE | grep ' = \"xfce4\"$' >/dev/null 2>&1; then DE=xfce;
+    elif `dbus-send --print-reply --dest=org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus.GetNameOwner string:org.gnome.SessionManager > /dev/null 2>&1` ; then DE=gnome;
+    elif xprop -root _DT_SAVE_MODE 2> /dev/null | grep ' = \"xfce4\"$' >/dev/null 2>&1; then DE=xfce;
     fi
 }