EX-773 lustre: Support RDMA only pages

EX-773 lustre: Support RDMA only pages

Some memory architectures and CPU-offload cards with
on-board memory do not map data pages into the CPU
address space. Allow RDMA of data directly into those
pages without accessing contents.

Therefore, made changes to prevent doing checksum on
these type of pages.

Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I189c34893ffa500ed275f2a1f79e8fb817a2489d
Reviewed-on: https://review.whamcloud.com/37454
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/42002
Reviewed-by: Wang Shilong <wshilong@whamcloud.com>