when a packer server has more then one NIC, Packer can often
select the wrong http server using {{ .HTTPIP }}. We extend the
variables file to include an http_server_address which can be set
to the IP address of the correct NIC. This configuration propagates down
to the http_bind_address directive of the builder and the boot_command
entered on the guest VM. Adding 0.0.0.0 as a reasonable default as it
preserves comptability with packers default behavior.
This commit was required to get Packer to build the ubuntu guest
successfully in our environment
Additional Reading:
https://github.com/hashicorp/packer/issues/9973https://www.packer.io/docs/builders/vmware/vsphere-iso#http-directory-configuration
