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# Type of request: This is a ...

[x] bug report
[ ] feature request

# Detailed description

In the `ReceiveMessageResult` of the SQS service, I saw this XML from localstack:

```
...
<MessageAttribute>
     <Name>encoding</Name>
    <Value>
        <DataType>String</DataType>
        <StringValue><![CDATA[gzip]]></StringValue>
    </Value>
</MessageAttribute>
...
```

The `<![CDATA[gzip]]>` is slightly different from AWS, which doesn't wrap the value in a `<!CDATA[[]]>` section. This shouldn't be a problem for XML parsers that accept both plain characters and CDATA sections for this element, but the XML parser I was using did not, which causes an error when running the code against localstack but not when running the code against AWS. There is obviously a bug in the XML parser as well, but I thought that I should at least post this here since it is different than what AWS SQS does.

## Expected behavior

MessageAttribute::Value elements should not be wrapped in `CDATA` sections.

## Actual behavior

MessageAttribute::Value elements all seem to be wrapped in `CDATA` sections.

# Steps to reproduce

Send a message to the SQS service which contains some custom message attributes, then make a ReceiveMessageRequest.

## Command used to start LocalStack

`docker run --env "SERVICES=sqs" localstack/localstack`

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)

...

return dict([(k, v) for k, v in object.items() if k in attributes])
def in_docker():
    return config.in_docker()
def has_docker():
    try:
        run('docker ps')
        return True
    except Exception:
        return False
def get_docker_container_names():
    return bootstrap.get_docker_container_names()
def path_from_url(url):
    return '/%s' % str(url).partition('://')[2].partition('/')[2] if '://' in url else url
def is_port_open(port_or_url, http_path=None, expect_success=True, protocols=['tcp']):
    port = port_or_url
    host = 'localhost'
    protocol = 'http'
    protocols = protocols if isinstance(protocols, list) else [protocols]
    if isinstance(port, six.string_types):
        url = urlparse(port_or_url)
        port = url.port
        host = url.hostname
        protocol = url.scheme
    nw_protocols = []
    nw_protocols += ([socket.SOCK_STREAM] if 'tcp' in protocols else [])
    nw_protocols += ([socket.SOCK_DGRAM] if 'udp' in protocols else [])
    for nw_protocol in nw_protocols:
        with closing(socket.socket(socket.AF_INET, nw_protocol)) as sock:
            sock.settimeout(1)
            if nw_protocol == socket.SOCK_DGRAM: