Error on undefined

[Thibault Charbonnier]

Not sure if this is the intended behaviour or not, so this is not a PR, but:

it('should fail with undefined', function (done) {
  validate(undefined, function (err, valid) {

  });

  done();
});

 HAR Spec
    1) should fail with undefined
    ✓ should fail with empty object
    ✓ should fail with empty array
    ✓ should fail on bad "log.version"
    ✓ should fail on bad "log.creator"
    ✓ should not fail with full example


  5 passing (5ms)
  1 failing

  1) HAR Spec should fail with undefined:
     TypeError: Cannot read property 'log' of undefined
      at validate (eval at <anonymous> (/Users/thibaultcha/Desktop/har-validator/node_modules/is-my-json-valid/node_modules/generate-function/index.js:55:21), <anonymous>:5:11)
      at module.exports (/Users/thibaultcha/Desktop/har-validator/src/index.js:7:15)
      at Context.<anonymous> (/Users/thibaultcha/Desktop/har-validator/test/validator.js:10:5)
      at Test.Runnable.run (/Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runnable.js:218:15)
      at Runner.runTest (/Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runner.js:374:10)
      at /Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runner.js:452:12
      at next (/Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runner.js:299:14)
      at /Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runner.js:309:7
      at next (/Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runner.js:248:23)
      at Object._onImmediate (/Users/thibaultcha/Desktop/har-validator/node_modules/mocha/lib/runner.js:276:5)
      at processImmediate [as _immediateCallback] (timers.js:345:15)

[Ahmad Nassri]

yep, should certainly assert for objects only ...