fix packer volume size definition

Author: sjpb

packer/openstack.pkr.hcl

@@ -175,7 +175,6 @@ source "openstack" "openhpc" {
   networks = var.networks
   floating_ip_network = var.floating_ip_network
   security_groups = var.security_groups
-  volume_size = var.volume_size
 
   # Input image:
   source_image = "${var.source_image[var.os_version]}"