LU-1944 ldlm: Add another net_latency to recoverry timer.

LU-1944 ldlm: Add another net_latency to recoverry timer.

Add another net_latency to this request deadline, i.e.
we need add 2 net_latency to extend the recovery timer,
one for balance rq_deadline (see ptl_send_rpc), one for
resend the req to server.

Signed-off-by: Wang Di <di.wang@whamcloud.com>
Change-Id: I6cb6e57358f4fe32ae2ac8d982af6ce03b68014b
Reviewed-on: http://review.whamcloud.com/4351
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>