LU-7475 lnet: ensure buffer config symmetry

LU-7475 lnet: ensure buffer config symmetry

When showing the configuration, make sure to add a buffers block
in the YAML output, if routing is configured, in order to allow
the same YAML block to be fed back for configuration to LNet.

Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Change-Id: I3b269edf5b3688b500bbb3656c367bc82fff6b68
Reviewed-on: http://review.whamcloud.com/17370
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>