allow users to set image_uuid instead of name, this allows the use of openstack community images (#7283)

contrib/terraform/openstack/modules/compute/variables.tf

@@ -134,4 +134,20 @@ variable "extra_sec_groups" {
 
 variable "extra_sec_groups_name" {
   type = string
-}
+}
+
+variable "image_uuid" {
+  type = string
+}
+
+variable "image_gfs_uuid" {
+  type = string
+}
+
+variable "image_master" {
+  type = string
+}
+
+variable "image_master_uuid" {
+  type = string
+}