Trivial fix shebang in keystone's fernet-node-sync.sh.j2

Change-Id: I86aeafccd2a2bff1d89a40785e1a6715097bb849
(cherry picked from commit f1cbff6)

Author: keuko

ansible/roles/keystone/templates/fernet-node-sync.sh.j2

@@ -1,4 +1,4 @@
-!/bin/bash
+#!/bin/bash
 
 set -o errexit
 set -o pipefail