LU-4658 fld: reset rc to 0 before resend fld lookup req

LU-4658 fld: reset rc to 0 before resend fld lookup req

Reset rc to 0 before resend fld lookup req, otherwise resend will
exit in fld_client_rpc before send request.

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I030262615be3c360aeb399eae3f90736c15ebf98
Reviewed-on: http://review.whamcloud.com/9333
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>