LU-18338 build: fix Ubuntu kernel signature check

LU-18338 build: fix Ubuntu kernel signature check

The Ubuntu kernel signature was checked by searching for
CONFIG_VERSION_SIGNATURE from autoconf.h. However, in
Ubuntu kernel 6.11.0-061100-generic, CONFIG_VERSION_SIGNATURE
is not defined. We can search for UTS_UBUNTU_RELEASE_ABI
from utsrelease.h.

Test-Parameters: trivial mdtcount=4 mdscount=2 \
  clientdistro=ubuntu2404 testlist=sanity

Test-Parameters: trivial mdtcount=4 mdscount=2 \
  env=SANITY_EXCEPT="255c" \
  clientdistro=ubuntu2204 testlist=sanity

Change-Id: I62e74ef936bbbf4e85130965cfff35aa7aa3be5e
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56613
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>