LU-6636 libcfs: minor fix in cfs_hash_for_each_relax()

LU-6636 libcfs: minor fix in cfs_hash_for_each_relax()

cfs_hash_for_each_relax() should break iteration when callback
returns non-zero value.

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: I92d35be4b11931cae252646ab2d1f8e5599037f1
Reviewed-on: http://review.whamcloud.com/14927
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>