targetcli can't detect if block exported with WT or WB

[nefelim4ag]

AFAIK targetcli can't change emulate_write_cache to 1 for block target driver
But target_core_iblock internaly detect WB support on device and export this to initiator
http://elixir.free-electrons.com/linux/latest/source/drivers/target/target_core_iblock.c#L833

So i think it's better show in cli gui WB/WT of exported device

$ ls -al /dev/disk/by-partuuid/a3e6a650-40c8-4ec2-ba42-33591f86cbae 
lrwxrwxrwx 1 root root 10 May  5 15:54 /dev/disk/by-partuuid/a3e6a650-40c8-4ec2-ba42-33591f86cbae -> ../../sdc1

$ grep . /sys/class/block/sdc/queue/write_cache 
write back

  | | o- wbtest ...................... [/dev/disk/by-partuuid/a3e6a650-40c8-4ec2-ba42-33591f86cbae (0 bytes) write-thru deactivated]
  | | | o- alua ................................................................................................... [ALUA Groups: 1]
  | | |   o- default_tg_pt_gp ....................................................................... [ALUA state: Active/optimized]