Revert "count-objects: output "KiB" instead of "kilobytes""

This reverts commit 44c69657a3daa6a9a187c3abca38931b53a97510; human
users can use "count-objects --human-readble" to get more readable
output anyway. Changing output of a command whose output may already
been read by tools is a risky proposition, compared to possible
breakages.