(#2112) Ensure CHORIA_SRV_DOMAIN is actually getting used

[treydock]

The logic to pull config defaults from an environment variable is only used when a config has a default. This adds empty string default for SRV domain which will trigger the logic to pull a default value also from the CHORIA_SRV_DOMAIN environment variable.

[treydock]

Got a local build working on Mac and did this:

$ export CHORIA_SRV_DOMAIN=dev.company.net
$ ./choria-0.28.0-darwin-amd64 tool config
<SNIP>
Connectivity:

       Main Collective: mcollective
           Collectives: mcollective
      Service Registry: disabled
            SRV Domain: dev.company.net

[ripienaar]

Are you 100% sure you updated? For me this works fine:

% export CHORIA_SRV_DOMAIN=dev.company.net
% choria tool config srv
.....
            SRV Domain: dev.company.net
.....
Configuration item: plugin.choria.srv_domain

║        Value: dev.company.net
║          URL: https://choria.io/docs/deployment/dns/
║    Data Type: string
║  Environment: CHORIA_SRV_DOMAIN
║
║ The domain to use for SRV records, defaults to the domain the
║ server FQDN is in
╙─
% choria --version
0.99.0.20240209

[ripienaar]

There's definitely something pretty weird going on, let me check, this should be working but testing in a docker container for example it does not.

I am not sure why yet but the exact same binary works in normal OS but not in docker, are you by any chance in docker?