Presto, chango!
The statusbar now has a (non-functional) KLed on its
right side. If you want it on the left, move the new
lines to the top of initStatusBar().

The public accessor is KLed* KStars::diskLED()
The relevant functions to call are diskLED()->on() and
diskLed()->off() (or diskLED()->toggle()).

(BTW, FYI: this is going to be used to indicate when the
disk is being accessed to dynamically load more stars.
It will probably be configured to only show up for debug
builds, or at least will be hidden by default)