Don't pass loidCreated header if we don't have it.
Don't pass loidCreated header if we don't have it.

It's possible to have loid and not loidCreated cookies
from inbound requests. In fact, this will always be the
case when we have server-signed loids. This patch fixes
an exception when we try to call `toISOString()` on an
invalid date, that was being created because we passed the
default empty string value for `loidCreated` to the Date
constructor. In general, we just shouldn't pass the
cookie header if we don't really have a loidCreated anyway.

ajacksified/reddit-mobile,ajacksified/reddit-mobile,ajacksified/reddit-mobile,ajacksified/reddit-mobile