Updated with correct syntax to access default_tags variable.

contrib/terraform/aws/modules/vpc/outputs.tf

@@ -16,6 +16,6 @@ output "aws_security_group" {
 }
 
 output "default_tags" {
-    value = "${default_tags}"
+    value = "${var.default_tags}"
 
 }

contrib/terraform/aws/output.tf

@@ -24,5 +24,5 @@ output "inventory" {
 }
 
 output "default_tags" {
-    value = "${default_tags}"
+    value = "${var.default_tags}"
 }