Send token on error message.

[sbernard31]

When en error occured on a CoAP request, the response does not contain the Token. It seems this is a bug.

See CoAP specification :

"2.2. Request/Response Model ...

   Client              Server       Client              Server
      |                  |             |                  |
      |   CON [0xbc90]   |             |   CON [0xbc91]   |
      | GET /temperature |             | GET /temperature |
      |   (Token 0x71)   |             |   (Token 0x72)   |
      +----------------->|             +----------------->|
      |                  |             |                  |
      |   ACK [0xbc90]   |             |   ACK [0xbc91]   |
      |   2.05 Content   |             |  4.04 Not Found  |
      |   (Token 0x71)   |             |   (Token 0x72)   |
      |     "22.5 C"     |             |   "Not found"    |
      |<-----------------+             |<-----------------+
      |                  |             |                  |

I propose this patch which change a very small amount of code, but maybe this is not the best way.
Probably the lwm2m_handle_packet function should be refactored because it begins to be long, but I do not feel to change it :), I do not manage this part of code enough.

[dnav]

This is indeed a bug.
The whole token mechanism needs to be reworked. This is the TODO item " - Add token in every message".
I will pull your change once the project is part of the Eclipse Foundation. (See issue #30)

[sbernard31]

Oups, sry I just do 2 other pull request :/

[dnav]

No problem. At least they are logged.

[jvermillard]

@sbernard31 can you push the PR on the new eclipse repo: http://github.com/eclipse/wakaama ?
Thanks

[dnav]

Project moved to http://github.com/eclipse/wakaama