Update ZooKeeper to 3.4.6

- Updated ZooKeeper to current stable version. (ONOS-1347)
- There are some references in scripts under old-scripts,
  which has not been updated.

Change-Id: Iac96c46ee7e821bcc0e471a5c8cd8a3165a4b439
diff --git a/ramcloud-build-scripts/MakefragPrivateTop b/ramcloud-build-scripts/MakefragPrivateTop
index 0369292..1d58c06 100644
--- a/ramcloud-build-scripts/MakefragPrivateTop
+++ b/ramcloud-build-scripts/MakefragPrivateTop
@@ -1,4 +1,4 @@
 # rewrite to match your environment
 ZOOKEEPER_LIB := /usr/lib/x86_64-linux-gnu/libzookeeper_mt.a
-ZOOKEEPER_DIR := ~/zookeeper-3.4.5
+ZOOKEEPER_DIR := ~/zookeeper-3.4.6