Don't display unreachable address

src/freedombone-controlpanel

     echo -n "IPv4: $(get_ipv4_address)/$(get_external_ipv4_address)"
     ipv6_address="$(get_ipv6_address)"
     if [ ${#ipv6_address} -gt 0 ]; then
-        echo "    IPv6: ${ipv6_address}"
+        if [[ "$ipv6_address" != *'unreachable'* ]]; then
+            echo "    IPv6: ${ipv6_address}"
+        fi
     fi
     echo ''
     echo ''