Normally, the fs suite overrides the kernel branch whenever the kernel client
is used, according to the matrix of configs. This prevents easily testing a new
kernel with the -k option to teuthology-suite. So, using the base config passed
to the script, detect if an alternate testing kernel is desired and use that
instead.

The scheduler still needs to do some work:

$ teuthology-suite ... --verbose -k wip-pdonnell-i66704 --filter k-testing
...
2024-10-18 00:29:43,875.875 DEBUG:teuthology.suite.merge:base kernel {'branch': 'wip-pdonnell-i66704', 'kdb': 1, 'sha1': '745cacd8f31e50d7f3b6039bbd8c9a8dfc07bf03', 'flavor': 'default'}
2024-10-18 00:29:43,875.875 DEBUG:teuthology.suite.merge:overriding testing kernel with {'branch': 'wip-pdonnell-i66704', 'kdb': 1, 'sha1': '745cacd8f31e50d7f3b6039bbd8c9a8dfc07bf03', 'flavor': 'default'}

vs.

$ teuthology-suite ... --verbose --filter k-testing
...
2024-10-17 20:04:52,265.265 DEBUG:teuthology.suite.merge:base kernel {'branch': 'distro', 'kdb': 1, 'sha1': 'distro'}

Which will only select jobs using the "testing" kernel.

See-also: ceph/teuthology#2008
Fixes: https://tracker.ceph.com/issues/68603
Signed-off-by: Patrick Donnelly pdonnell@ibm.com

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