all Tails builds are broken currently since Linux API was bumped in
sid (#7656). feature/linux-3.14-2 fixes this => please review'n'merge
ASAP.
If nobody has time to handle this review'n'merge within 3 days, I'll
merge it myself, to unblock the development process.
An ISO built from this branch two days ago passes the automated test
suite entirely (had to re-run the USB feature a few times due to
#6092, as usual these days, oh well). That ISO had kernel 3.14.13-1.
Since then, 3.14.13-2 entered sid, but the only changes are about mips
and s390 architectures, and udebs, so it should not change anything
for us.