dir auths write consensuses to disk after creation

This step happens after we make each consensus flavor, and before we
worry about sigs or anything. That way if Tor crashes, or if we fail to
get enough sigs, we still have a chance to know what consensus we wanted
to make.

src/feature/dirauth/dirvote.c

@@ -3462,6 +3462,15 @@ dirvote_compute_consensuses(void)
       pending[flav].body = consensus_body;
       pending[flav].consensus = consensus;
       n_generated++;
+
+      /* Write it out to disk too, for dir auth debugging purposes */
+      {
+        char *filename;
+        tor_asprintf(&filename, "my-consensus-%s", flavor_name);
+        write_str_to_file(get_datadir_fname(filename), consensus_body, 0);
+        tor_free(filename);
+      }
+
       consensus_body = NULL;
       consensus = NULL;
     }