LU-17045 lnet: ksocklnd-config report errors on cmd failure

LU-17045 lnet: ksocklnd-config report errors on cmd failure

Make sure that ksocklnd-config script logs an error if any of the
commands it attempts to execute fail.

The script already does log a warning if it finds any of the routes
it is intending to add already exist. It should also report if any
of the command execution failed to make the user aware that MR routing
setup could not be applied.

Test-Parameters: trivial
Signed-off-by: Frank Sehr <fsehr@whamcloud.com>
Change-Id: If5a240d224f6a45015d1fc1a9d0a8df58ed661e4
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52327
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Oleg Drokin <green@whamcloud.com>