Mention that case is important when prompting before writing.
Mention that case is important when prompting before writing.

Change-Id: I35cb42d4120b734f6332fb671787f1e76e0c6832

BUG=chromium-os:10093
TEST=manual

Run the installer. It should now say

  "You must enter 'YES' (all uppercase) to continue: "
  "If you're sure that's correct, enter 'DoIt' now (case is important): "

Review URL: http://codereview.chromium.org/5612009

ccaapton/vboot_reference,marineam/seismograph,acorn-marvell/vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,marineam/seismograph,coreboot/vboot,ccaapton/vboot_reference,geekboxzone/mmallow_external_vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,coreboot/vboot,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,ionave/seismograph,marineam/seismograph,ccaapton/vboot_reference,marineam/seismograph,ionave/seismograph,ccaapton/vboot_reference,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,ionave/seismograph,coreboot/vboot,acorn-marvell/vboot_reference