Control: getinfo entry-guards report down-since

If the guard unreachable_since variable was set, the status "up" was
reported which is wrong. This adds the "down" status followed by the
unreachable_since time value.

Fixes #14184

Signed-off-by: David Goulet <dgoulet@ev0ke.net>

src/or/entrynodes.c

@@ -1666,6 +1666,9 @@ getinfo_helper_entry_guards(control_connection_t *conn,
         } else if (e->bad_since) {
           when = e->bad_since;
           status = "unusable";
+        } else if (e->unreachable_since) {
+          when = e->unreachable_since;
+          status = "down";
         } else {
           status = "up";
         }