Update README status about distributedlog project (#245)

Descriptions of the changes in this PR:

As distributedlog modules are merged into Apache BookKeeper, update the README status to reflect the project status.

See BP-26 for current status.
diff --git a/README.md b/README.md
index 9af2f35..77a14c0 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,9 @@
 
 _Apache DistributedLog project graduated from Incubator at July 2017. It is now a sub-project of Apache BookKeeper._
 
+The core components of _Apache DistributedLog_ has been merged as part of _Apache BookKeeper_. The development of _Apache DistributedLog_ has been moved under BookKeeper.
+See [BP-26: Move distributedlog library as part of bookkeeper](http://bookkeeper.apache.org/bps/BP-26-move-distributedlog-core-library/) for more details.
+
 ## Features
 
 #### High Performance