keystone: Add post-keystone.sh script support

This post-keystone.sh script will be mounted at /usr/bin/post-script.sh
It will help to do execute tasks after keystone service is up. For example:
endpoints and users creating.

Signed-off-by: Munoz, Obed N <obed.n.munoz@intel.com>

keystone/bootstrap.sh

@@ -47,4 +47,9 @@ if [[ $? == 1 ]]; then
     openstack role create user
 fi
 
+# Run post-keystone.sh script, if it exists
+if [ -f "/usr/bin/post-keystone.sh" ]; then
+   /usr/bin/post-keystone.sh
+fi
+
 tail -f /var/log/*