verify_rootfs_chksum.sh: drop unused script

Nothing in the tree seems to reference this, nor any documentation.

BUG=None
TEST=precq passes

Change-Id: I39b473985546daf856b016d88d5f07ecc3ef326d
Reviewed-on: https://chromium-review.googlesource.com/1498114
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
1 file changed