#915 Add last_cmd to GET /clients API

"last_cmd" json object contains information of the last command executed
by the correspondent client. For now, it only includes "result" string
property, which stores "success" if the last command finished correctly
or "failure" on the contrary.

To populate "result" property, this commit also adds "last_cmd_result"
enum attribute to og_client struct. Client response processing fills
this attribute according to its success.

Clients in WOL_SENT state always have last_cmd->result = "unknown".

Request: GET /clients

Response: 200 OK
{
  "clients": [
    {
      "addr": "10.141.10.102",
      "state": "WOL_SENT",
      "last_cmd": {
        "result": "unknown"
      }
    },
    {
      "addr": "10.141.10.101",
      "state": "OPG",
      "speed": 1000,
      "last_cmd": {
        "result": "success"
      }
    },
    {
      "addr": "10.141.10.100",
      "state": "OPG",
      "speed": 1000,
      "last_cmd": {
        "result": "failure"
      }
    }
  ]
}

0 files changed, 0 insertions, 0 deletions