LU-11025 uapi: introduce OBD_CONNECT2_CRUSH

LU-11025 uapi: introduce OBD_CONNECT2_CRUSH

Introduce a new connect flag OBD_CONNECT2_CRUSH to indicate whether
client or server supports new directory hash type 'crush'.

Test-parameters: trivial

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I073ab65eddf502c016f30ad535740f3d9a77459f
Reviewed-on: https://review.whamcloud.com/36774
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>