filtering out EC2DHCPOption for the default VPC

[bentterp]

I think we are missing a way of filtering out the EC2DHCPOption for the default VPC.
I have a preset for leaving the normal resources created for the default VPC in place, except for the dhcp option set:

presets:
  defaultvpc:
    filters:
      EC2VPC:
      - property: IsDefault
        value: "true"
      EC2InternetGateway:
      - property: DefaultVPC
        value: "true"
      EC2InternetGatewayAttachment:
      - property: DefaultVPC
        value: "true"
      EC2Subnet:
      - property: DefaultVPC
        value: "true"
      EC2RouteTable:
      - property: DefaultVPC
        value: "true"

Of course this depends on #691

But there is nothing which indicates that a DHCP option set is used by the default VPC, so I have nothing to filter on.

[ga-paul-t]

I have raised #694 to address this. I must have missed this out with my original work