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/onos.sh b/onos.sh
index 0818a49..8bbae2c 100755
--- a/onos.sh
+++ b/onos.sh
@@ -10,7 +10,7 @@
 # $ONOS_LOGBASE    : base name of log output file (onos.`hostname`)
 # $RAMCLOUD_HOME   : path of root directory of RAMCloud repository (~/ramcloud)
 # $RAMCLOUD_BRANCH : branch name of RAMCloud to use (master)
-# $ZK_HOME         : path of root directory of ZooKeeper (~/zookeeper-3.4.5)
+# $ZK_HOME         : path of root directory of ZooKeeper (~/zookeeper-3.4.6)
 # $ZK_LIB_DIR      : path of ZooKeeper library (/var/lib/zookeeper)
 # $ZK_LOG_DIR      : path of ZooKeeper log output directory (~/ONOS/onos-logs/zk-`hostname`)
 # $JVM_OPTS        : JVM options ONOS starts with
@@ -60,7 +60,7 @@
 
 LOGDIR=${ONOS_LOGDIR:-${ONOS_HOME}/onos-logs}
 
-ZK_HOME=${ZK_HOME:-~/zookeeper-3.4.5}
+ZK_HOME=${ZK_HOME:-~/zookeeper-3.4.6}
 ZK_CONF=${ZK_CONF:-${ONOS_CONF_DIR}/zoo.cfg}
 ZK_CONF_TEMPLATE=${ONOS_TEMPLATE_DIR}/zoo.cfg.template
 # Adding ONOS_HOST_NAME dir since file name (zookeeper.out) cannot be controlled.