[OE-core] [PATCH 4/4] wic: fix restoring of original fstab

[Diego Rondini]

Hi Ed,

> Wic updates fstab if mount points are specified in .wks.
> After partition images are created the original fstab is restored.
> However, if exception is raised when partition image being prepared
> wic doesn't restore original fstab. This can cause duplication of
> added lines in fstab when 'wic create' runs next time.
> 
> Wrapping call of 'prepare' method and restoring original fstab
> even if exception occurs should fix this.
> 
> [YOCTO #11633]
> 
> Signed-off-by: Ed Bartosh <ed.bartosh at linux.intel.com>

I've applied the patch locally, and deliberately caused some WicError 
exceptions: the resulting fstab correctly has only one mount entry. So this 
seems to fix #11633.

Tested-by: Diego Rondini <diego.rondini at kynetics.com>

Thanks for taking care of this,
Diego