ospfd: fix "no ip ospf passive" command

ospfd: fix "no ip ospf passive" command

This command is currently always treated as an "unset" command, assuming
that active is the default type of the interface. In reality, the default
type of the interface can be changed using "passive-interface default"
command. Both "no" and regular commands can be "set" commands, depending
on the default value. They are treated as an "unset" when there's already
a config of the opposite type.

All this logic is in ospf_passive_interface_update.

Fixes #9240.

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