systemctl: color ignored exit status in yellow, not red

systemctl: color ignored exit status in yellow, not red

If the executable path is prefixed with "-", an exit code of the command
normally considered a failure (i.e. non-zero exit status or abnormal exit
due to signal) is recorded, but has no further effect and is considered
equivalent to success.

Let's honor this with `systemctl status`, and color ignored exit status
in yellow, not red.