The following patch makes the "Network" window display computers in the
workgroup listed in the smb.conf file instead of "WORKGROUP" if the workgroup
name hasn't been set in GConf.

The implementation is as discussed with Alex on IRC:
 1) modify the gnome-vfs SMB method to make smb://X-GNOME-DEFAULT-WORKGROUP/
    display the contents of the workgroup name listed in the SMBCCTX (which
    comes from the smb.conf config file).
 2) modify the gnome-vfs "Network" method to use "X-GNOME-DEFAULT-WORKGROUP"
    as the default workgroup name if none is listed in GConf, instead of
    defaulting to "WORKGROUP".

While this isn't a substitute for exposing the /system/smb/workgroup GConf key
somewhere in the preferences, it does mean that if Samba has been set up on the
workstation Gnome will default to browsing that same workgroup.