Until now gnt-network connect expected the network,
mode, link, and optionally groups as positional arguments.

To be able to pass vlan info too, use the `--nic-parameters`
option, just like gnt-cluster client to pass the desired
mode, link, and vlan. Missing values will be filled with the
default ones.

Do not support old argument passing since mode and link should
be arguments with variable length and this violates bash completion
generation rules.

Update QA to pass the new option instead of deprecated arguments.

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>