vmargs -name and -cookie mappings can't be hidden

[RJ]

I had mappings for vmargs node name and distributed_cookie marked as hidden, but the release fails to start because the bin script checks for them in the generated conf file, ignoring the app.config:

https://github.com/tsloughter/rebar3_cuttlefish/blob/master/priv/bin_script#L99

I'll probably need to change this at some point, since i'd rather not expose the cookie and node name in the customer config file (not things I want customers to change).

Not a huge problem, ticketing for the record.

[tsloughter]

Good point.