title: Terraform error - RDS Cluster FinalSnapshotIdentifier is required when a final snapshot is required
body: <p>I am new to Terraform. I am using Terraform to write AWS scripts. I am getting an error while performing <strong>Terraform Destroy</strong>. Terraform script is</p>
  
  <pre><code>resource "aws_rds_cluster" "aurora-cluster-ci" {
    cluster_identifier        = "aurora-cluster-ci"
    engine                    = "aurora-mysql"
    availability_zones        = ["us-east-1a", "us-east-1b", "us-east-1c"]
    database_name             = "${var.rds_dbname}"
    master_username           = "${var.rds_username}"
    master_password           = "${var.rds_password}"
    backup_retention_period   = 5
    engine_version            = "5.7.16"
    preferred_backup_window   = "07:00-09:00"
    apply_immediately         = true
    final_snapshot_identifier = "ci-aurora-cluster-backup"
    skip_final_snapshot       = true
  }
  </code></pre>
  
  <blockquote>
    <p><strong>Terraform Destroy</strong> throws an error "aws_rds_cluster.aurora-cluster-ci: RDS Cluster
    FinalSnapshotIdentifier is required when a final snapshot is required"</p>
  </blockquote>
  
  <p>I have "final_snapshot_identifier" key in my script. </p>