[Tails-dev] [review'n'merge:1.4] feature/9340-Linux-from-Str…

Hi,

as explained on #9340, without this change, our build system will very
soon start producing unbootable ISO images. Please merge into stable,
testing, devel and feature/jessie.

Filed #9341 for the next steps (once Linux 4.0 migrates to Debian
testing).

Cheers,
--
intrigeri