staging/lustre/utils: missing setting echo seq for getattr/setattr

It should set echo seq before do echo getattr/setattr, otherwise
echo_client will regard it as the object with MDT0 sequence.

[picked echo client part for upstream kernel submission]
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3267
Lustre-change: http://review.whamcloud.com/6263


Signed-off-by: wang di <di.wang@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>