LU-17175 tests: fix sanity-krb5 test_5 in interop mode

LU-17175 tests: fix sanity-krb5 test_5 in interop mode

With newer servers, the lsvcgssd daemon is automatically restarted
when the server needs to process a gss request. So do not error out
if a file system access succeeds whereas the daemon was explicitly
killed.

Test-Parameters: trivial
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I52ec49ca584f07100699274fe3a52ea28d227c17
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54103
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Aurelien Degremont <adegremont@nvidia.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>