In I8f168fde04bf9e421d9a39e91a041512bf4f2b79 tox.ini was enhanced to
allow use of upper-constraints.txt.  By default the master branch was
used which will results in failures as things progress/diverge.

Pin it to the stable/mitaka branch.

Change-Id: Ic59546fbc176c36cb8726042b6243ec14c941ef1

This will force pip install to use the upper-constraints.txt specified
version of pip modules. When you don't do this, you are out on the
bleeding edge and become unstable everytime some python library in the
world changes in a way that you don't expect.

The script is needed because it cleans up the conflicting entry that
corresponds to the client before applying it to source based
installation.

Change-Id: I8f168fde04bf9e421d9a39e91a041512bf4f2b79
Closes-Bug: 1563038
cherry-picked from commit 8585bd60325e7d9b08aa6043afc00fb83d2b2356

Add possibility to generate release notes to glanceclient.
We need this because it helps to prepare good documentation
and provide useful info to Openstack users.

Change-Id: Ifce2df8ac5f3a14518a758d748964e7201a75291

"Python 3.3 support is being dropped since OpenStack Liberty."
written in following URL.
https://wiki.openstack.org/wiki/Python3

And already the infra team and the oslo team are dropping py33
support from their projects.

Since we rely on oslo for a lot of our work, and depend on infra
for our CI, we should drop py33 support too.

Change-Id: Id80bab700d0535b919be6b8f42e0c1561557e45e
Closes-Bug: #1526170

As of mitaka, the infra team won't have the resources available to
reasonably test py26, also the oslo team is dropping py26 support
from their libraries. sine we rely on oslo for a lot of our work,
and depend on infra for our CI, we should drop py26 support too.

Change-Id: I50eff4ea33358791cc4f139b3b369489c38f7e5c
Closes-Bug: 1519510

Caching is enabled by default from pip version 6.0

More info:
https://testrun.org/tox/latest/config.html#confval-downloadcache=path
https://pip.pypa.io/en/stable/reference/pip_install/#caching

Change-Id: I235e737bc6375c8e09d86818195b6aba8a0c332c

We removed pypy's gate a few weeks ago as it's been failing for some
time. This means we're not supporting it anymore. Therefore, it should
be ok to remove it from the tox file.

Change-Id: Iac9bf4775794b8d097c0c5cae0337f14fa2fa25c

To resolve "db type could not be determined" when running tox
for the first time py34 environment need to laucnhed before py27.

Change-Id: Id46e9e9400974fcb6eebb4516bf4b3e69a6570e2
Closes-Bug: #1489059