Adjust details specific to GCP.

def adj_nodes_gcp(gcp_nodes):
    """Adjust details specific to GCP."""
    for node in gcp_nodes:
        node.cloud = "gcp"
        node.cloud_disp = "GCP"
        node.private_ips = ip_to_str(node.private_ips)
        node.public_ips = ip_to_str(node.public_ips)
        node.zone = node.extra['zone'].name
    return gcp_nodes