* support network attachments in net-vpc module
* support network attachments in net-address module
* fix examples
* fix examples
* add support for psc interfaces to compute-vm module
null address results in following error:
Error creating GlobalAddress: googleapi: Error 400: Invalid value for field 'resource.address': ''. The field is not a valid IP address or does not match the given prefix length, invalid
Error creating Address: googleapi: Error 400: Invalid value for field 'resource.purpose': 'SHARED_LOADBALANCER_VIP'. Shared LoadBalancer VIP IPv6 address reservation is not supported., invalid
This PR changes variable region's default value in example tests to real region value.
Some of the modules parse the region name to decide whether to create regional or zonal resources.