Make managix scripts properly executable

Most of the scripts managix was using were missing the shebang at the beginning of the script.
This can be problematic if one uses a shell besides bash. This patch fixes that.

Change-Id: Ie7722f832d0d25bec049e123a0ed1570d0aeb650
Reviewed-on: https://asterix-gerrit.ics.uci.edu/286
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Raman Grover <ramangrover29@gmail.com>
diff --git a/asterix-installer/src/main/resources/zookeeper/stop_zk b/asterix-installer/src/main/resources/zookeeper/stop_zk
index 9bef86e..84d9b74 100644
--- a/asterix-installer/src/main/resources/zookeeper/stop_zk
+++ b/asterix-installer/src/main/resources/zookeeper/stop_zk
@@ -1,3 +1,5 @@
+#!/usr/bin/env bash
+
 ZK_HOME=$1
 shift 1
 for zk_host in  $@