component/trafficserver: Use patch directly from source

Thanks to shacache it will be cached anyway, and it allows to easily refer
to the source changes and eventual discussion.

component/trafficserver/buildout.cfg

@@ -28,7 +28,7 @@ md5sum = 4f4d1e7de19c77157be0c2a825b31026
 shared = true
 patch-options = -p1
 patches =
-  ${:_profile_base_location_}/trafficserver-8.1-stale-negative-cache-not-returnable.patch#e1a2f8a23f00cee1301ccf1a84e46763
+  https://github.com/apache/trafficserver/commit/3d0492f7276bb93aff499f637ff843c45908b193.patch#f23dd950acc0395fe7bc72264987c013
 configure-options =
   --with-openssl=${openssl:location}
   --with-pcre=${pcre:location}

component/trafficserver/trafficserver-8.1-stale-negative-cache-not-returnable.patch

---- trafficserver-8.1.1/proxy/http/HttpTransact.cc.orig	2020-12-01 00:30:26.000000000 +0100
-+++ trafficserver-8.1.1/proxy/http/HttpTransact.cc	2021-01-11 11:35:41.946893735 +0100
-@@ -5752,6 +5752,7 @@
- HttpTransact::is_stale_cache_response_returnable(State *s)
- {
-   HTTPHdr *cached_response = s->cache_info.object_read->response_get();
-+  HTTPStatus cache_response_code = cached_response->status_get();
- 
-   // First check if client allows cached response
-   // Note does_client_permit_lookup was set to
-@@ -5760,6 +5761,12 @@
-   if (!s->cache_info.directives.does_client_permit_lookup) {
-     return false;
-   }
-+  // We don't serve stale negative cache.
-+  if (cache_response_code == HTTP_STATUS_INTERNAL_SERVER_ERROR || cache_response_code == HTTP_STATUS_GATEWAY_TIMEOUT ||
-+      cache_response_code == HTTP_STATUS_BAD_GATEWAY || cache_response_code == HTTP_STATUS_SERVICE_UNAVAILABLE) {
-+    TxnDebug("http_trans", "[is_stale_cache_response_returnable] stale negative cache");
-+    return false;
-+  }
-   // Spec says that we can not serve a stale document with a
-   //   "must-revalidate header"
-   // How about "s-maxage" and "no-cache" directives?