Add titles to the times on zuul status's page

Currently there are two times displayed on zuuls status page
(http://status.openstack.org/zuul/). It is not immediately obvious
what these times represent.

This change adds a title to each time so that when hovered over a
description is available.

Change-Id: I17563851e76dcc09fd7d71e8946622ba24fc3ea5
Merge "Add titles to the times on zuul status's page"