rgw/s3: dump Message field in Error response even if empty

some clients like veeam fail to decode the response if Message is missing

Fixes: https://tracker.ceph.com/issues/59433

Signed-off-by: Casey Bodley <cbodley@redhat.com>

src/rgw/rgw_common.cc

@@ -368,8 +368,7 @@ void dump(req_state* s)
     s->formatter->open_object_section("Error");
   if (!s->err.err_code.empty())
     s->formatter->dump_string("Code", s->err.err_code);
-  if (!s->err.message.empty())
-    s->formatter->dump_string("Message", s->err.message);
+  s->formatter->dump_string("Message", s->err.message);
   if (!s->bucket_name.empty())	// TODO: connect to expose_bucket
     s->formatter->dump_string("BucketName", s->bucket_name);
   if (!s->trans_id.empty())	// TODO: connect to expose_bucket or another toggle