[Installer] Shows install aborted if you click begin without first selecting an "onto" volume

[scottmc]

If you don't pick an "onto" from the drop down box, and just want to use the default selection, Installer shows "Installation aborted." Perhaps the "Onto" should default to a blank line to force the user to select an onto volume prior to clicking on Begin. Or have the Begin button greyed out until an onto volume is picked, or both even.

I kept pressing the Begin button and kept getting an installation aborted message and I thought something must be wrong with my hard drive. I finally figured that I needed to click the onto once and then it would work.

[korli]

Fixed in hrev27051.