router_get_fallback_dirserver_by_digest uses authorities, should use fallbacks
router_get_fallback_dirserver_by_digest looks like it was copied from router_get_trusteddirserver_by_digest. The comment was changed, but the set of servers searched was not.
router_get_fallback_dirserver_by_digest is only used in connection_dir_client_reached_eof to record 503 "too busy" messages. The impact of this issue is that only authorities are getting marked as "too busy". Unless a user specifies their own fallbacks, and those fallbacks are busy, they'll never see this issue.
Bug in 5c51b3f1f0d4c394392, released in 0.2.4.7-alpha.
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