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.

(cherry picked from commit e879434df5)

src/systemctl/systemctl-show.c

@@ -584,7 +584,7 @@ static void print_status_info(
 
                 good = is_clean_exit(p->code, p->status, EXIT_CLEAN_DAEMON, NULL);
                 if (!good) {
-                        on = ansi_highlight_red();
+                        on = p->ignore ? ansi_highlight_yellow() : ansi_highlight_red();
                         off = ansi_normal();
                 } else
                         on = off = "";