LU-12945 lnet: Disable zero copy when running on VM

LU-12945 lnet: Disable zero copy when running on VM

When running on a hypervisor platform zero copy buffers
may still be referenced when write queue size is zero

So when running on a hypervisor push the zero copy size limit
above max payload size of 16M.

Use the hypervisor test added to linux v4.14-119-g79cc74155218
and provide a replacement for earlier kernels.

kernel-commit: 79cc74155218316b9a5d28577c7077b2adba8e58

Cray-bug-id: LUS-8072
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I5582a6aa8da6f48deafaf13d60cf67a09d7a7231
Reviewed-on: https://review.whamcloud.com/37300
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Alexey Lyashkov <alexey.lyashkov@hpe.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>