LU-10800 lnet: Revert "LU-10270 lnet: remove an early rx code"

LU-10800 lnet: Revert "LU-10270 lnet: remove an early rx code"

This reverts commit c3894ff80fe4b48f2d62ea33ddc54fb5891e6484. Dropping
early receives caused pings to be ignored and interacted badly with
dynamic discovery.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I99a87a8f58ea67c59d5e85b964295472c2e15de4
Reviewed-on: https://review.whamcloud.com/31675
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Amir Shehata <amir.shehata@intel.com>
Reviewed-by: Doug Oucharek <dougso@me.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>