Refrain from mentioning old bug in a warning

changes/bug25477

@@ -0,0 +1,3 @@
+  o Minor bugfixes (logging):
+    - Refrain from mentioning bug 21018, as it is already fixed.
+      Fixes bug 25477; bugfix on 0.2.9.8.

src/or/rendcache.c

@@ -908,9 +908,7 @@ rend_cache_store_v2_desc_as_client(const char *desc,
     if (n_intro_points <= 0) {
       log_warn(LD_REND, "Failed to parse introduction points. Either the "
                "service has published a corrupt descriptor or you have "
-               "provided invalid authorization data, or (maybe!) the "
-               "server is deliberately serving broken data in an attempt "
-               "to crash you with bug 21018.");
+               "provided invalid authorization data.");
       goto err;
     } else if (n_intro_points > MAX_INTRO_POINTS) {
       log_warn(LD_REND, "Found too many introduction points on a hidden "