HOTFIX: @Vitalliumm discovered a typo in CookieJar

Original message: https://twitter.com/vitalliumm/status/301220038323613697
This was affecting date comparison/espiration in the
CookieJar.

Typical case of "I have no idea how it did work so far".

Issue: http://code.google.com/p/phantomjs/issues/detail?id=1068