LU-15644 llog: don't report warning in no error case

LU-15644 llog: don't report warning in no error case

Fix wrong check which includes rc == 0 valid case wronly

Fixes: 53d946a1222 (LU-15644 llog: don't replace llog error with -ENOTDIR)
Test-Parameters: trivial
Signed-off-by: Mikhail Pershin <mpershin@whamcloud.com>
Change-Id: Id6e7b2cd42b4769765c67d418552a13f048ea050
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/55337
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>