Avoid infinite loops in ni_lldp_agent_update

Signed-off-by: Olaf Hering <olaf@aepfle.de>
lldp: disabled lldp support (fate#313671)
Merge pull request #209 from olafhering/olh-misc
Merge pull request #210 from mtomaschewski/lldp

lldp: disabled lldp support (fate#313671) -- rejected feature