add "done" after "Updating partition details..."

This addresses a usability problem. Some users are confused when they
switch to the console and see this message, thinking they have to wait.

Examples:
http://forum.xda-developers.com/showthread.php?t=2498492
http://androidforums.com/verizon-galaxy-s3-all-things-root/718376-twrp-recovery-update-question.html

Change-Id: Ib44773998c2ef1b8b821f3b8876218e11a7de357