message: fix: set default node props to null instead of ''
diff: @@ -525,11 +525,11 @@ function addNode (zwaveNode) {
  this.nodes[nodeId] = {
  id: nodeId,
  - deviceId: '',
  - manufacturer: '',
  - manufacturerId: '',
  - productType: '',
  - productId: '',
  + deviceId: null,
  + manufacturer: null,
  + manufacturerId: null,
  + productType: null,
  + productId: null,
  name: this.storeNodes[nodeId] ? this.storeNodes[nodeId].name : '',
  loc: this.storeNodes[nodeId] ? this.storeNodes[nodeId].loc : '',
  values: {},
  @@ -541,7 +541,7 @@ function addNode (zwaveNode) {
  failed: false,
  lastActive: null,
  interviewCompleted: false,
  - firmwareVersion: '',
  + firmwareVersion: null,
  isBeaming: false,
  isSecure: false,
  keepAwake: false,
  