This patchset changes version of python-troveclient package version
used in tests.
So far, version from global constrain file was used [1].
In order to achive this, a local constrain file for tests requirements
has been added. This made it possible to override global constrain
versions.
[1] openstack/requirements/upper-constraints.txt
Change-Id: Ic4383f0249e5bd367461f63f66217af959aefba4
Signed-off-by: Marcin Piwowarczyk <m.piwowarczy@samsung.com>