resource/aws_emr_cluster: Return empty kerberos_attribute if realm is missing
resource/aws_emr_cluster: Return empty kerberos_attribute if realm is missing

terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws,nbaztec/terraform-provider-aws,terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws,Ninir/terraform-provider-aws,nbaztec/terraform-provider-aws,terraform-providers/terraform-provider-aws,Ninir/terraform-provider-aws,kjmkznr/terraform-provider-aws,nbaztec/terraform-provider-aws,terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws,Ninir/terraform-provider-aws,Ninir/terraform-provider-aws,nbaztec/terraform-provider-aws