LU-15644 llog: don't replace llog error with -ENOTDIR

LU-15644 llog: don't replace llog error with -ENOTDIR

The dt_try_as_dir() contains check for object existence
which is reported as -ENOTDIR after all. In case of llog
that goes to upper level and cause error reporting to
console. It is not relevant neither by error code nor by
debug level

Patch skips check for object existence in case of llog,
it is excessive anyway.
Debug level is reduced as well to don't spawn console
messages in case of -ENOENT, -ESTALE or -EIO errors

Fixes: 1ebc9ed460 ("LU-15902 obdclass: dt_try_as_dir() check dir exists")
Signed-off-by: Mikhail Pershin <mpershin@whamcloud.com>
Change-Id: Id404204566898a6ac2e258b7824491effc5fc92e
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55151
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>