LU-6356 ptlrpc: ret -ECONNREFUSED if not context found in req

LU-6356 ptlrpc: ret -ECONNREFUSED if not context found in req

Return -ECONNREFUSED instead of -ENOMEM in sptlrpc_req_get_ctx()
if no context is found in req.
It it more graceful?

Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Change-Id: If1b142199a94d1976093a7d26a05e49a63f50469
Reviewed-on: http://review.whamcloud.com/14043
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Andrew Perepechko <andrew.perepechko@seagate.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>