Major changes in 2.91.3 are:
* Remove autorun and automount machinery, it moved to gnome-settings-daemon
* Don't install the 'File Management Properties' binary; there's now
  a capplet in gnome-control-center for the autorun system settings.
* Fix interaction with the session manager
* Don't use gtk_[h|v]_separator_new
* Identify OGG Vorbis files as music in the search UI
* Require new gnome-desktop