Misleading doc comment for `use_network_action_output_cache`

[lf-]

FYI this comment suggests that the behaviour believed in in #246 is the case. https://github.com/facebook/buck2/blob/b41f89757bdbef3b3993f9b0af5074b9d39a3421/app/buck2_server/src/daemon/state.rs#L151-L159

It sounds from #246 that this comment is straight up not the intended use case, so I'm very confused what the setting is for. I indeed want the same thing as them which is that http_archives with a given hash survive daemon restarts.