no-deprecated-api throws a TypeError with global assignment

[not-an-aardvark]

Hi!

I'm using:

• Node v6.9.1
• eslint@3.9.1
• eslint-plugin-node@3.0.0
• .eslintrc.yml:

  rules:
    node/no-deprecated-api: error
  plugins:
    - node
  env:
    node: true
  

• foo.js:

  fs = require('fs');

When I run node_modules/.bin/eslint foo.js, a TypeError is thrown:

TypeError: Cannot read property 'references' of null
    at eachReadReferences (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:146:13)
    at checkVariable (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:353:9)
    at checkDestructuring (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:249:17)
    at checkProperties (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:323:21)
    at path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:431:29
    at Array.forEach (native)
    at eachReadReferences (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:146:49)
    at checkCommonJsModules (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:416:13)
    at EventEmitter.Program:exit (path/to/node_modules/eslint-plugin-node/lib/rules/no-deprecated-api.js:486:13)
    at emitOne (events.js:96:13)