When authority certificates expire, give a better error message
On master, I have a test directory authority on i386 macOS 10.12 which can't download certificates. The directory authority had been down (asleep) for a while, and on update to the new master, it said:
May 10 19:02:28.645 [notice] Tor 0.3.1.0-alpha-dev (git-0266c4ac819d9c83) running on Darwin with Libevent 2.1.8-stable, OpenSSL 1.0.2k, Zlib 1.2.11, Liblzma N/A, and Libzstd N/A.
...
May 10 19:03:15.000 [warn] Got a certificate for lemonpeasy, but we already have it. Maybe they haven't updated it. Waiting for a while.
May 10 19:03:15.000 [warn] Got a certificate for triplepeak, but we already have it. Maybe they haven't updated it. Waiting for a while.
May 10 19:03:15.000 [warn] Got a certificate for Betty, but we already have it. Maybe they haven't updated it. Waiting for a while.
May 10 19:03:15.000 [warn] Got a certificate for Evelyn, but we already have it. Maybe they haven't updated it. Waiting for a while.
May 10 19:03:15.000 [warn] Got a certificate for albert, but we already have it. Maybe they haven't updated it. Waiting for a while.
May 10 19:03:15.000 [warn] Got a certificate for missionary, but we already have it. Maybe they haven't updated it. Waiting for a while.
...
May 10 19:04:16.000 [warn] Looks like we need to download a new certificate from authority 'triplepeak' at ...
May 10 19:04:16.000 [warn] Looks like we need to download a new certificate from authority 'Betty' at ...
I suspect this bug might have been introduced in 0.3.1. Or, it might be due to the fact our test network consensus is broken. Or it could be because we're on mixed versions (which should work).