Request bodies are incorrectly added to the Swagger spec when no headers are included in the request

[ctuckz]

1. Make a POST request which includes body data, but does not include a content-type header.
   api2swagger -X POST -e https://api.github.com -o ./testSwagger.json -d '{\"test\":\"test\"}'
2. Note that the outputted Swagger file has an invalid schema in the parameters section:

"parameters": [
    {
    "in": "body",
    "name": "body",
    "description": "Request Payload Body",
    "required": true,
    "schema": "'{\"test\":\"test\"}'"
    }
]

Several errors are also displayed in the Swagger Editor when pasting in the schema.

When the content-type header is included in the request, the section looks like:

{
    "name": "body",
    "in": "body",
    "schema": {
        "description": "",
        "type": "object",
        "properties": {
            "test": {
                "type": "string",
                "minLength": 1
            }
        },
        "required": [
            "test"
        ]
    },
    "description": "",
    "required": true
}

Api2Swagger should handle the case when a content-type header is not provided along with a request body by either:

1. Ignoring the request body
2. Displaying an error message
3. Assuming a content-type of application/json and trying to parse the request body. This follows Swagger's behavior of assuming application/json when no media type is provided in the produces or consumes section.