[oe] [jethro] Backport 12e31ce9d6065086fa0a84733f7b45664d41b7e9 from master

[Richard Leitner]

Hello,
please backport commit 12e31ce9d6065086fa0a84733f7b45664d41b7e9 from
master to jethro branch!
This is needed for samba to work on a readonly rootfs!

> commit 12e31ce9d6065086fa0a84733f7b45664d41b7e9
> Author: Johannes Pointner <johannes.pointner at br-automation.com>
> Date:   Fri Apr 15 11:23:42 2016 +0200
>
> samba: add volatile file to support readonly rootfs
>
> This patch adds a volatile file for samba which was removed by the
> update from 3.6.25 to 4.1.12. This file is necessary to build a image
> that uses the read-only-rootfs feature.
>
> Signed-off-by: Johannes Pointner <johannes.pointner at br-automation.com>
> Signed-off-by: Martin Jansa <Martin.Jansa at gmail.com>
> Signed-off-by: Joe MacDonald <joe_macdonald at mentor.com>

Thank you!

Kind regards,
Richard