LU-11469 lnet: fix "debug recovery" output

Don't print out anything from

lnetctl debug recovery [--local|--peer]

if there are no NIs on the recovery queues.

Test-Parameters: trivial
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Icf4d5e2f1e3eefafce81dcc73525a4dd9a36d009
Reviewed-on: https://review.whamcloud.com/33310
Reviewed-by: Doug Oucharek <dougso@me.com>
Reviewed-by: Sonia Sharma <sharmaso@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>