staging/lustre/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>
Reviewed-on: http://review.whamcloud.com/14927
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6636


Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>