Directory authorities on master are causing clock skew warns on every reachability test

A growing number of relay operators started complaining tonight of lines like

Sep 21 05:22:01.021 [Warning] Received NETINFO cell
with skewed time from server at 76.73.17.194:9090. It seems that our
clock is ahead by 15969 days, 3 hours, 22 minutes, or that theirs is behind.
Tor requires an accurate clock to work: please check your time and date
settings.

That's 1970. Mike maintains his clock is correct. And also he upgraded to git master recently.

In parallel, git commit 1d0ba9 does

-  /* Timestamp. */
-  set_uint32(cell.payload, htonl((uint32_t)now));
+  /* Timestamp, if we're a relay. */
+  if (! conn->handshake_state->started_here)
+    set_uint32(cell.payload, htonl((uint32_t)now));

That means every outgoing connection from a directory authority puts a time of 0 in the netinfo cell during its handshake. And relays are programmed to log_warn if they get told a time from an authority that disagrees with their opinion about what time it is.