RHEL5 kickstart needs to mount cdrom in postinst

[Chris Lumens]

> I have several systems here, laptops and compact desktops, that cannot 
> pull a CD in; once it's ejected I need to push the tray or CD back in.
> 
> I think it's worth a bug report; perhaps you can allege a design fault.

Yep, this was because some steps got moved around.  It's tracked by bugs
238711 and 239002, and has been fixed in rawhide besides.

- Chris