Remove unnecessary versions from comments

Summary: D11106 missed version bumping some comments. Instead of maintaining version numbers in the comments this patch removes them.

Test Plan: Inspect comments.

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, Fabien, PiRK

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, Fabien, PiRK

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D11112