image_to_usb.sh didn't handle the case where the devices were being
automounted.
build_image.sh didn't handle the case where the version string > ~14
characters.
Review URL: http://chromereview.prom.corp.google.com/1173161
git-svn-id: svn://chrome-svn/chromeos/trunk@108 06c00378-0e64-4dae-be16-12b19f9950a1
