hab pkg [pro][de]mote doesn't report correct platform of package pro/demoted

[mrysanek]

E.g.:
When running on Linux, "hab pkg promote foo/bar/1.2.3/20220102030405", if successful, will always report
"Promoted package foo/bar/1.2.3/20220102030405 (x86_64-linux)"
...regardless of whether the package is Linux or Windows.

Converse is also true, when running on Windows, the platform reported is always x86_64-windows regardless of the package's actual platform.

The CORRECT package is pro/demoted, this is a report-only issue.