lldpad: Add '-p' option to suppress PID file creation

The 'ping' command can be used to figure out if the daemon is
alive. So to make it useful we should be adding the daemon PID
to the reply message.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
vdptest: Use 'ping' command to get lldpad PID

Instead of reading the PID file the vdptest program can use
the 'ping' reply to get the lldpad PID.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
lldpad.init: Use 'ping' message to check lldpad daemon

Instead of reading the PID file we can use the 'ping' command
from dcbtool to check if the daemon is alive.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
lldpad: Add '-p' option to surpress PID file creation

A PID file is not always necessary, so add option '-p' to
suppress PID file handling.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>