Apply NVMe bugfix from Google that bjf asked for

[Khaled El Mously]

bjf asked for this fix in the google kernels:

https://lore.kernel.org/patchwork/patch/974880/

It looks like it's actually needed in bionic/master as well

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.18.0-7.8

---------------
linux (4.18.0-7.8) cosmic; urgency=medium

  * linux: 4.18.0-7.8 -proposed tracker (LP: #1789459)

  * pmtu.sh fails on 4.18 kernel (LP: #1789436)
    - SAUCE: Revert "vti6: fix PMTU caching and reporting on xmit"

 -- Seth Forshee <email address hidden> Tue, 28 Aug 2018 11:08:51 -0500

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-bionic' to 'verification-done-bionic'. If the problem still exists, change the tag 'verification-needed-bionic' to 'verification-failed-bionic'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!