LU-9667 lnet: Userspace control to show lnd conn stats

LU-9667 lnet: Userspace control to show lnd conn stats

This patch adds the functions to display lnd connection
stats of each connection under an lnd peer using the
lnetctl command -

lnetctl peer stats --lnd

Change-Id: Icbb3a1e45bb487a5cb58b46094540bc522ae728e
Signed-off-by: Sonia Sharma <sharmaso@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/33421
Tested-by: Jenkins
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Maloo <maloo@whamcloud.com>