I have tested the changed in this pull request against the current tip of hg-review and TortoiseHg 3.2.1. I found no merge conflicts, and I was able to verify that the script does not require updates.
I looked over the list of libraries that the update_tortoisehg_libs.py script copies into TortoiseHg\library.zip, and I found that this changeset still accomplishes its desired goal: it causes the update_tortoisehg_libs.py script to cease overwriting libraries that are currently included with TortoiseHg.
I have also verified that windows users must still execute this script before using hg-review, or else they receive the "abort: no module named Cookie" error. Once this script executes, hg-review runs normally on my Windows machine.
Is there anything else you would like to see done? I can give you another pull request if you need one, but I'm not sure what you would have me change... ?