fix the measure memory size test since the structures turn smaller

misc/spec/mix/measure_memory_spec.rb

@@ -15,10 +15,10 @@ describe "Measure Memory" do
     }
   end
 
-  message_estimate_size = 174
-  channel_estimate_size = 536
-  subscriber_estimate_size = 200
-  subscriber_estimate_system_size = 6560
+  message_estimate_size = 175
+  channel_estimate_size = 272
+  subscriber_estimate_size = 160
+  subscriber_estimate_system_size = 6530
 
   it "should check message size" do
     channel = 'ch_test_message_size'

misc/spec/nginx_configuration.rb

@@ -64,6 +64,8 @@ error_log         <%= error_log %> debug;
 master_process    <%= master_process %>;
 daemon            <%= daemon %>;
 worker_processes  <%= nginx_workers %>;
+worker_rlimit_core  500M;
+working_directory <%= nginx_tests_tmp_dir %>;
 
 events {
   worker_connections  1024;