metrics data on FallbackDir does not represent the tor source

Don't know when this happened but for tor-0.4.8.13 & tor-0.4.8.14 some relays were removed from fallback_dirs.inc but did not loose their FallbackDir-Flag on metrics.

As an example you can look up this relay: https://metrics.torproject.org/rs.html#details/62F4994C6F3A5B3E590AEECE522591696C8DDEE2