VPC Export Creates Output Without Value

[kuhnboy]

Describe the bug
Calling export on a VPC creates a export without a value

To Reproduce
var vpc = new VpcNetwork(this, "vpc", new VpcNetworkProps { Cidr = ipNetwork, EnableDnsHostnames = true, EnableDnsSupport = true, MaxAZs = AvailabilityZones });
vpc.Export();

Results in: agc-dev failed: ValidationError: Template format error: Every Outputs member must contain a Value object
Template format error: Every Outputs member must contain a Value object

Output
Outputs:
netvpcPublicSubnetIDsB4AEB182:
Value:
Fn::Join:
- ","
- - Ref: netvpcPublicSubnet1Subnet4CD4B50E
- Ref: netvpcPublicSubnet2SubnetDA258F98
- Ref: netvpcPublicSubnet3SubnetEEF98931
Export:
Name: agc-tst:netvpcPublicSubnetIDsB4AEB182
netvpcPrivateSubnetIDs0D06D2E1:
Value:
Fn::Join:
- ","
- - Ref: netvpcPrivateSubnet1Subnet44E8FA8C
- Ref: netvpcPrivateSubnet2Subnet4971F090
- Ref: netvpcPrivateSubnet3Subnet0D065BB7
Export:
Name: agc-tst:netvpcPrivateSubnetIDs0D06D2E1
netvpcVpcIdAE1C9B5B:
Value:
Ref: netvpc8AAA4B80
Export:
Name: agc-tst:netvpcVpcIdAE1C9B5B

Expected behavior
Exports are not created if they have no value.

Version:

• OS: Win10
• Programming Language: C#
• CDK Version: 0.28.0

[jogold]

This has been fixed in #2219 (9e87661) but not yet released.