Update entrynodes unit test for dirs

We no longer base our opinion on whether someone is a directory solely
on the routerstatus we might have for that relay, but also on a
routerinfo. Remove logic in test checking that. This broke unit tests in
05f7336624.

Reported by toralf on #tor-dev, thanks!

src/test/test_entrynodes.c

@@ -162,9 +162,6 @@ populate_live_entry_guards_test_helper(int num_needed)
        False, all guards should have made_contact enabled. */
     tt_int_op(entry->made_contact, OP_EQ, 1);
 
-    /* Since we don't have a routerstatus, all of the entry guards are
-       not directory servers. */
-    tt_int_op(entry->is_dir_cache, OP_EQ, 0);
   } SMARTLIST_FOREACH_END(entry);
 
   /* First, try to get some fast guards. This should fail. */