Bug 1070047 - Upgrade chaijs to a newer version (rebased)

without use:
[test-agent-test/unit/chai_test.js] chai expect interface:
     expected false to be truthy
with use:
[test-agent-test/unit/chai_test.js] chai expect interface:
     Error: expected false to be truthy
      at chaiAssert (app://test-agent.gaiamobile.org/common/test/helper.js:48:1)
      at (anonymous) (app://test-agent.gaiamobile.org/common/vendor/chai/chai.js:1196:1)
      at get (app://test-agent.gaiamobile.org/common/vendor/chai/chai.js:3669:22)
      at (anonymous) (app://test-agent.gaiamobile.org/test/unit/chai_test.js:6:5)
      at wrapper (app://test-agent.gaiamobile.org/common/test/mocha_generators.js:62:19)
      at run (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:3709:7)
      at runTest (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:4081:5)
      at (anonymous) (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:4127:7)
      at next (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:4007:1)
      at (anonymous) (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:4016:7)
      at next (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:3964:1)
      at (anonymous) (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:3984:5)
      at (anonymous) (app://test-agent.gaiamobile.org/common/vendor/mocha/mocha.js:4932:28)
firefox not support stack trace!