Have Http Liveness Probe report "Unhealthy" on connection failure instead of "Unknown"

Based on #3041: modfiy HTTP liveness probe so when it fails due to connection issues, it will return an "Unhealthy" status instead of an "Unknown" status thus forcing kubelet to restart the container.
The reasoning behind this change is that if Kubelet can't establish a connection to the container service, considering they're on the same host,  it is fair to assume that the container is in an unhealthy state, and should be restarted.
probably should log the error and
```go
return Unhealthy, nil
```

Since there is in fact, no error from this functions perspective.