api node: always pass cluster conf to node FW parser

api node: always pass cluster conf to node FW parser

As else the parsing may lead to "false positive" errors, as cluster
wide aliases and other definitions are seemingly missing.

Reproducer:
* add *cluster* alias
* add+enable *host* rule using that alias
* enable FW on DC and node level
* go to Node -> FW -> Options
* check journal/syslog for error like:
> pveproxy[1339680]: /etc/pve/nodes/dev6/host.fw (line 3) - errors in rule parameters: IN ACCEPT -source test123 -p tcp -sport 22 -log nolog
> pveproxy[1339680]:   source: no such alias 'test123'

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>