[OpenAFS] Ubuntu 20.04 gets (OEM) kernel 5.14 and AFS from ppa:openafs/stable fails

[Jan Henrik Sylvester]

On certain hardware (for example Dell OptiPlex 7090 and Dell Latitude 
7420), the graphical update of Ubuntu 20.04 will automatically install 
packages like oem-somerville-cubone-rkl-meta or 
oem-somerville-squirtle-meta. These replace kernel 5.13 
(generic-hwe-20.04) with 5.14 (linux-oem-20.04c/d).

openafs-client 1.8.8-0ppa1~ubuntu20.04.1 from ppa:openafs/stable does 
compile on kernel 5.14, but there are runtime failures, which are 
mentioned in the OpenAFS 1.8.8.1 changelog for Ubuntu 22.04:

   * Import upstream patch to improve support for linux 5.14 (avoiding
     a runtime error when the set_page_dirty operation is requested)

Doing a simple backport of the 22.04 package 1.8.8.1 to 20.04 fixes the 
problem.

ppa:openafs/stable needs an update to 1.8.8.1 and focal-updates should 
at least get the patch mentioned above. Thanks a lot.

Best wishes,
Jan Henrik