LU-6929 libcfs: typo in cfs_hash_for_each_relax()

LU-6929 libcfs: typo in cfs_hash_for_each_relax()

In cfs_hash_for_each_relax(), rc != 0 means caller want to break
the iteration, so we should only continue the iteration when rc
is zero.

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: I9666cd26ebe93627009bd03b7bbd341a65beaddf
Reviewed-on: http://review.whamcloud.com/15813
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>