LU-11872 utils: don't follow link files in default

LU-11872 utils: don't follow link files in default

We actually don't support operation on link files itself for now.
As a first step, let's skip link files for now in default,
otherwise, it cause unexpected behavior.

Lustre-change: https://review.whamcloud.com/34111
Lustre-commit: 004b80da5c4b2a7cf4f4885b43c9edec76cd2493

Test-Parameters: trivial testlist=sanity-quota
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Change-Id: Ib0069ed1982e26984c6cf093f0803bf4a2208fe1
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Gu Zheng <gzheng@ddn.com>
Reviewed-on: https://review.whamcloud.com/35392
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>