Make max_message_size customizable

Change-Id: Id9f55733c41a46d4566cfef2ecf41c353a7aa2b4
diff --git a/metadata/service/log_collector/single.yml b/metadata/service/log_collector/single.yml
index 5160c35..d7a53fd 100644
--- a/metadata/service/log_collector/single.yml
+++ b/metadata/service/log_collector/single.yml
@@ -5,7 +5,9 @@
 parameters:
   _param:
     log_collector_poolsize: 100
+    log_collector_max_message_size: 262144
   heka:
     log_collector:
       enabled: true
       poolsize: ${_param:log_collector_poolsize}
+      max_message_size: ${_param:log_collector_max_message_size}