message: fix(server): wrong ref to flow in sample flogo.json
diff: "handlers": [
  {
  "action": {
  - "ref": "github.com/project-flogo/contrib/action/flow",
  + "ref": "github.com/project-flogo/flow",
  "data": {
  "flowURI": "res://flow:aws_iot_sample"
  },
  "handlers": [
  {
  "action": {
  - "ref": "github.com/project-flogo/contrib/action/flow",
  + "ref": "github.com/project-flogo/flow",
  "data": {
  "flowURI": "res://flow:hello_world"
  }
  