remove the hive's local build of agent closures

A rebuild or create downloads the closure the swarm built and applies it; with none to deploy it fails and changes nothing. hive-priv takes a store path instead of an internal/meta commit and builds nothing.

hive-priv/src/closure.rs

@@ -170,7 +170,7 @@ async fn realise_with(
         let cache = Cache::read(url, dir, owner)?;
         let mut cmd = tokio::process::Command::new("nix-store");
         cmd.args(realise_args(store_path, &cache));
-        match run_bounded(cmd, REALISE_TIMEOUT, None)
+        match run_bounded(cmd, REALISE_TIMEOUT)
             .await
             .context("running nix-store")?
         {
@@ -342,8 +342,8 @@ mod tests {
         assert!(Cache::read(Some(URL), &dir.join("nowhere"), me).is_err());
     }
 
-    /// Missing facts reach the caller as `not available`, which its prebuild
-    /// answers by building.
+    /// Missing facts reach the caller as `not available`, which a rebuild
+    /// reports as a closure that cannot be pulled.
     #[tokio::test]
     async fn without_the_root_files_the_answer_is_not_available() {
         let nowhere = scratch().join("nowhere");