ospfd: fix passive interface configuration

ospfd: fix passive interface configuration

Currently, passive interface flag is configured from the router node
using "passive-interface IFNAME". There are multiple problems with this
command:
- it is not in line with all other interface-related commands - other
  parameters are configured from the interface node using "ip ospf"
  prefix
- it is not in line with OSPFv3 - passive flag is configured from the
  interface node using "ipv6 ospf6 passive" command
- most importantly, it doesn't work correctly when the interface is in
  a different VRF - when using VRF-lite, it incorrectly changes the
  vrf_id of the interface and it becomes desynced with the actual state;
  when using netns, it creates a new fake interface and configures it
  instead of configuring the necessary interface

To fix all the problems, this commit adds a new command to the interface
configuration node - "ip ospf passive". The purpose of the command is
completely the same, but it works correctly in a multi-VRF environment.

The old command is preserved for the backward compatibility, but the
warning is added that it is deprecated because it doesn't work correctly
with VRFs.

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>