LU-11299 lnet: Cleanup rcd

LU-11299 lnet: Cleanup rcd

Cleanup all code pertaining to rcd, as routing code will use
discovery going forward and there will be no need to keep its own
pinging code.

test_215 looks at the routers file which had its format changed.
Update the test to reflect the change.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: If31caa3b5703df40b6ae0f758f2fe764991aa4f3
Reviewed-on: https://review.whamcloud.com/33187
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Tested-by: Jenkins