Add the 'startupdate' API call which allows you to queue a

system update

Valid args:

target : "chbranch/pkgupdate/fbsdupdate/fbsdupdatepkgs/standalone"
branch: "newbranch" - (Only used with chbranch target)
tag: "pkgng-1.6.9" - (Only used with standalone target)

REST Request:
-------------------------------
PUT /sysadm/update
{
   "action" : "startupdate",
   "target" : "pkgupdate"
}

REST Response:
-------------------------------
{
    "args": {
      "startupdate": {
        "queueid": "611c89ae-c43c-11e5-9602-54ee75595566",
        "command": "pc-updatemanager pkgupdate",
        "comment": "Task Queued"
        }
    }
}

WebSocket Request:
-------------------------------
{
   "args" : {
      "action" : "startupdate",
      "target" : "pkgupdate"
   },
   "name" : "update",
   "id" : "fooid",
   "namespace" : "sysadm"
}

WebSocket Response:
-------------------------------
{
  "args": {
    "startupdate": {
      "queueid": "611c89ae-c43c-11e5-9602-54ee75595566",
      "command": "pc-updatemanager pkgupdate",
      "comment": "Task Queued"
    }
  },
  "id": "fooid",
  "name": "response",
  "namespace": "sysadm"
}

src/server/library/sysadm-update.cpp

@@ -142,6 +142,7 @@ QJsonObject Update::startUpdate(QJsonObject jsin) {
   // Create a unique ID for this queued action
   QString ID = QUuid::createUuid().toString();
 
+  // Queue the update action
   DISPATCHER->queueProcess(ID, "pc-updatemanager " + flags);
 
   // Return some details to user that the action was queued