LU-9771 flr: read support for flr

LU-9771 flr: read support for flr

Avoid stale mirrors to read;
If preferred mirror is inaccessible, try next one, ndelay RPC
is implemented to make the error-out quick. ndelay RPC has
rq_no_delay bit set that can be applied to brw and lock RPC.

Test-Parameters: testlist=sanity-flr
Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: I52143079edd1566ecb3a734ed88dab19f882c2fc
Reviewed-on: https://review.whamcloud.com/29085
Tested-by: Jenkins
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>