Wrong actionType in POST /v2/op/update causes wrong error message generated by PEP

[fgalan]

Testing with Postman, the following request (wrong actionType) to CB directlty (without PEP)

POST /v2/op/update

{
	"actionType": "APPPEND",
	"entities": [
		{
			"id": "myEntity1",
			"type": "myType",
			"description": {
				"value": "My happy entity",
				"type": "Text"
			}
		}
	]
}

result in

400 Bad Request
Connection: Keep-Alive
Content-Length: 129
Content-Type: application/json
Date: Fri, 27 Apr 2018 14:08:37 GMT
Fiware-Correlator: 7aa8c866-4a24-11e8-a2c6-000c29173617

{
    "error": "BadRequest",
    "description": "invalid update action type: right ones are: APPEND, APPEND_STRICT, DELETE, REPLACE, UPDATE"
}

However, if the same request is done throguh PEP we get:

{
    "name": "UNEXPECTED_CONTENT_TYPE",
    "message": "The MIME content type received is not supported: undefined"
}

which obsivously is not correct.