ALB prefix should start/end with '/'

Fix of "The value of 'access_logs.s3.prefix' cannot start or end with '/'" error

variables.tf

@@ -5,7 +5,7 @@ variable "cdn_logs_path" {
 
 variable "alb_logs_path" {
   description = "Prefix for ALB logs."
-  default     = "alb/"
+  default     = "alb"
 }
 
 variable "s3_logs_path" {
@@ -20,4 +20,4 @@ variable "bucket" {
 variable "force_destroy" {
   default     = false
   description = "Allow remove bucket with its content."
-}
+}