only set up the port spy for 'port' health checks

[#83638700]

Signed-off-by: Atul Kshirsagar <atul.kshirsagar@gmail.com>
fall back on port check if none specified

...for backwards-compatibility

[#83638700]

Signed-off-by: Atul Kshirsagar <atul.kshirsagar@gmail.com>