remove bats test fixture

test/fixtures/amazon-ebs/ami_snapshot_tags.json

-{
-    "builders": [{
-        "type": "amazon-ebs",
-        "ami_name": "packer-test {{timestamp}}",
-        "instance_type": "m1.small",
-        "region": "us-east-1",
-        "ssh_username": "ubuntu",
-        "source_ami": "ami-0568456c",
-        "tags": {
-            "packer-test": "true",
-            "packer-id": "ami_snapshot_tags"
-        },
-        "ami_block_device_mappings": [
-            {
-                "device_name": "/dev/sde",
-                "volume_type": "standard"
-            }
-        ]
-    }]
-}