python3.pkgs.systemd: Fix compatibility with Python 3.10

[jtojnar]

Description of changes

Required for fail2ban to start correctly:

systemd/python-systemd#107

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[jtojnar]

Verified that after applying this patch, fail2ban starts without printing the following error on startup:

fail2ban.jail[556855]: INFO Creating new jail 'sshd'
fail2ban.jail[556855]: INFO Jail 'sshd' uses systemd {}
fail2ban.jail[556855]: INFO Initiated 'systemd' backend
fail2ban.filter[556855]: INFO   maxLines: 1
fail2ban.transmitter[556855]: WARNING Command ['server-stream', …] has failed. Received SystemError("PY_SSIZE_T_CLEAN macro must be defined for '#' formats")
fail2ban[556855]: ERROR NOK: ("PY_SSIZE_T_CLEAN macro must be defined for '#' formats",)

[AkechiShiro]

When is this going to be merged ? I'm just having errors with fail2ban due to this I believe, when I just did `nixos-rebuild test --upgrade :

fail2ban-server[64881]: ERROR: cannot import name 'MutableMapping' from 'collections' (/nix/store/6wiycdxh63mk4krdd75db0hshicna6yy-python3-3.10.4/li>

[AkechiShiro]

Thanks !