Missing check for version of nested messages during handling messages from database

[kbeker]

Quote from #857 blueprint:

receive/ endpoint
Since Concent creates responses on the fly, the client will always get a response containing a message created with Concent's version of golem-messages. Client can see this version in the Concent-Golem-Messages-Version HTTP header on the response.

If the response needs to contain a nested message taken from the database and that message is not compatible with Concent's version of golem-messages, Concent responds with ServiceRefused. The client is always required to stay on the same protocol version while communicating about the same subtask.

[PaweuB]

Pivotal:
https://www.pivotaltracker.com/story/show/163020955

[cameel]

Update: we'll respond with HTTP 404 if versions are not compatible.

[pawelkisielewicz]

There was no missing protocol version's validation of nested messages during handling messages from database. It was and still is validated if concent's protocol version is compatible with protocol version in task_to_compute of pending response. It is enough, because in clean method of Subtask is validated, that all stored messages connected with one Subtask have the same protocol version.

It is only need to change concent's response from ServiceRefused to Http404, it is done in referenced pull request