[vcloud_director] fix to input format for post_create_org_vdc_network

Noticed error in input format surrounding IpRanges, where input missing the IpRange elements (instead was just created in Generator)
Merge pull request #2487 from alphagov/vcd_fix_post_create_org_vdc_network

[vcloud_director] fix to input format for post_create_org_vdc_network