LU-18047 lnet: sanity-lnet test_260 wrong value

LU-18047 lnet: sanity-lnet test_260 wrong value

Added retries and delay in case values are not set in time.

Test-Parameters: trivial testlist=sanity-lnet
Signed-off-by: Frank Sehr <fsehr@whamcloud.com>
Change-Id: I6caa00e5fd7fb86ae55a593bed897f1dcaee1392
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55910
Tested-by: Maloo <maloo@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>