fix nmap parameters

closes: #2618
kill spurious space
finer global zone exclusion

closes: #2620
exclude incomplete LLDP results
better handling of multiple discovery protocols

The new algorithm is:
- start with LLDP
- complete with CDP:
 - for interface without known neighbor, just use CDP info
 - for interface with a known neighbor, check if the name match:
  - if it matches, assume it is the same neighbor, and complete LLDP info
  - if it doesn't, raise a warning, and delete LLDP info
- complete with EDP:
 - for interface without known neighbor, just use EDP info
 - for interface with a known neighbor, check if the name match:
  - if it matches, assume it is the same neighbor, and complete LLDP info
  - if it doesn't, raise a warning, and delete LLDP info
drop dead function
kill Registry module from inventory task

This is better handled by collect task
prevent warning for malformed group file

see: #2384
ooops
no warning if /proc/bus/input/devices is missing

/proc/bus/input/devices is not available in OpenVZ container
fix a warning with LXC 1.0
openvz: avoid duplicate VM

if libvirt is already available, we disable the openvz module.
simpler and more consistent with Qemu case

Moreover, it avoids a warning if virsh is not available.
update expected results
use SYSDESCR instead of SYSNAME for comparaison

Some CDP implementation apparently advertise mac address instead of host
name, so it seem safer to use a more consensual value.
recognize mac address from host name in CDP info
yet another CDP subtility
shorter error message
better variable name
shorter error message