If your goal is to eliminate certificate fingerprint warnings during push/pull, there’s a better way to do this. Use the [hostfingerprints] in .hg/hgrc (or ~/.hgrc — see comments).
[hostfingerprints]
server.example.org = 38:76:52:7c:87:26:9a:8f:4a:f8:d3:de:08:45:3b:ea:d6:4b:ee:cc
This will eliminate the warnings without eliminating the security checks.
Note: I see from your comments to another answer that you’ve already found this solution. I’m posting this anyway in case someone else has the same problem.