Switch upper-constraints URL to static location
Switch upper-constraints URL to static location

During the train cycle, a new static URL scheme was introduced for
upper-constraints URLs that allows us to switch locations based on
configuration and avoid timing windows with the requirements repo
branching. This updates upper-constraints links in the tox.ini file to
point to the newer more prefered location.

Change-Id: I8efbb24483d2a63a8abfa50e328fefb7ffd92e5f
Signed-off-by: Sean McGinnis <961eeb09b6d45516665e15b82e013282c4faf575@gmail.com>

openstack/python-designateclient