LU-11419 lfsck: lfsck_namespace_shrink_linkea() dead loop

LU-11419 lfsck: lfsck_namespace_shrink_linkea() dead loop

lfsck_namespace_shrink_linkea() may fall in dead loop if it tries
to delete XATTR_NAME_LINK.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I43e6e7917f8f89eb2cc873c8521cd3fbb528f495
Reviewed-on: https://review.whamcloud.com/33252
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>