added host prefix var

vars.tf

@@ -29,14 +29,10 @@ variable "ssh_private_key" {
 }
 
 variable "host_prefix" {
-  description = "format of host id. Adds the last three digits of floating ip to create the last part of the host ip"
+  description = "prefix of host id."
   default = "164.111.161.%s"
 }
 
-variable "host_id_formatting" {
-  description = 
-  default = "element(split(".", openstack_networking_floatingip_v2.ip_pool.address),3)"
-  
 variable "enable-dhcp" {
   description = "whether dhcp in enabled. defualt is true"
   default = true