Make sure fix works for non-slurm dry-run too

Author: amaslenn

src/cloudai/systems/slurm/slurm_system.py

@@ -761,6 +761,7 @@ def system_installables(self) -> list[Installable]:
 
     def complete_job(self, job: SlurmJob) -> None:
         out, _ = self.fetch_command_output(f"sacct -j {job.id} -p --noheader -X --format=NodeList")
-        nodelist = set(parse_node_list(out.splitlines()[0].strip().replace("|", "")))
+        spec = out.splitlines()[0] if out.splitlines() else out
+        nodelist = set(parse_node_list(spec.strip().replace("|", "")))
         to_unlock = [node for node in self.group_allocated if node.name in nodelist]
         self.group_allocated.difference_update(to_unlock)