Update jQuery Cookie to v1.2.0

Source

* https://github.com/carhartl/jquery-cookie/blob/v1.2.0/jquery.cookie.js

Change log

* https://github.com/carhartl/jquery-cookie/blob/v1.2.0/CHANGELOG.md

README

* https://github.com/carhartl/jquery-cookie/blob/v1.2.0/README.md

We're upgrading from an early alpha version of v1.1 (faa09dc).
The main change is the addition of $.removeCookie() for deleting cookies,
usage of $.cookie('key', null) has been deprecated.

We should eventually upgrade to v1.4.1, but that has a breaking change.
Namely, it drops support for $.cookie('key', null) which needs to be
replaced by $.removeCookie which didn't exist until v1.2.0.

Change-Id: I511138518fcd8bffc86fc3feaf5dbe253c7d786f