swarm-builder: an agent option whose eval failed is left out of the reply, not read as its default

hive-c0re/src/job_queue/exec/tests.rs

@@ -274,8 +274,8 @@ fn closure(cached: bool) -> AgentClosure {
         system: "x86_64-linux".to_owned(),
         built_unix: 1,
         cached,
-        private_users: false,
-        nix_builds: hive_types::NixBuilds::Host,
+        private_users: Some(false),
+        nix_builds: Some(hive_types::NixBuilds::Host),
     }
 }