Nomad native service health checks fail when using interpolated service address in job

[MattJustMatt]

Nomad version

1.6.2

Issue

Reproduction steps

1. Use Nomad service discovery
2. Set the address to a variable like the gce public IP address
3. Add an HTTP health check

Expected Result

The health checker uses the variable address from the service catalog (/v1/service/:name output:)

Actual Result

The health checks always fail with a parse error (using the string literal value)

Job file (if appropriate)

[jrasell]

Hi @MattJustMatt and thanks for raising this issue along with the PR. I'll take another look at the PR, when I next have a moment.