Make Diagnostics production parameter aware

[MuratUrsavas]

Acceptance Criteria

• Diagnostics has to recognize new Docker volume /var/nebra
• It should be able to create necessary scripts even for the devices already on field
• Diagnostics will be the primary responsible to track these environment variables

[shawaj]

Related to #444

[shawaj]

@MuratUrsavas we need to make sure this works for non Nebra devices. Currently it fails...

NebraLtd/hm-pktfwd#123

Maybe for non Nebra we can just have it put a value of none in the file?

[shawaj]

@MuratUrsavas I suppose the other way we could solve this is to just set all non-Nebra fleets to have a FREQ variable set to something like N/A (Non Nebra Miner)

Then we wouldn't need to make any code changes.

What do you think?

[MuratUrsavas]

@shawaj Actually I was expecting a mandatory FREQ parameter, but you're right. It has to be optional. Let me fix it.

[shawaj]

This one just fails silently already right @MuratUrsavas ?

https://github.com/NebraLtd/hm-diag/blob/master/setenv.sh

[MuratUrsavas]

@shawaj It's actually not failing. Just prompts an error if cannot reach them from both of the sources. But it continues to work if not exists.

[shawaj]

Perfect

[shawaj]

@MuratUrsavas @KevinWassermann94 guessing we can close this now?