nixos/acme: Remove dependency on system version for hash

This means that all systems running from master will trigger
new certificate creation on next rebuild. Race conditions around
multiple account creation are fixed in #106857, not this commit.

nixos/modules/security/acme.nix

@@ -104,12 +104,7 @@ let
     mkHash = with builtins; val: substring 0 20 (hashString "sha256" val);
     certDir = mkHash hashData;
     domainHash = mkHash "${concatStringsSep " " extraDomains} ${data.domain}";
-    othersHash = mkHash (
-      "${toString acmeServer} ${data.keyType}"
-      + (
-        optionalString (versionOlder "20.09" config.system.stateVersion) data.email
-      )
-    );
+    othersHash = mkHash "${toString acmeServer} ${data.keyType} ${data.email}";
     accountDir = "/var/lib/acme/.lego/accounts/" + othersHash;
 
     protocolOpts = if useDns then (