Addressed rubocop comments.

- Addressed PR comments. Changed set_perf_collection_object_list caller to only send up list of hosts marked for collection for a cluster.
- Removed code that was setting @temp[:cl_recs], it was not required to store Cluster Objects in @temp.

https://bugzilla.redhat.com/show_bug.cgi?id=1153047
https://bugzilla.redhat.com/show_bug.cgi?id=1145799