LU-12678 lnet: discard LNetMEInsert

This function is unused and has never been used.
It is not used by cray-dvs - the other user of LNet.

So discard it.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I35a012c390ae1a7ae9d601f12cf5da1b56d4eb6d
Reviewed-on: https://review.whamcloud.com/36858
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>