Addressed rubocop comments.

- Addressed PR comments.
- Renamed set_perf_collection_object_list method to perf_capture_enabled_host_ids= changed it's caller to only send up list of host ids marked for collection for a cluster. Removed querying for hosts in controller.
- 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