stop leaking service as a global var

the tls code was leaking out $service as a global variable, which
was causing all manner of confusing errors in grenade trying to
use that variable name. All lower case vars should be localize.

Change-Id: I74fa597f20ee7c714cab83490b42d874ea93db02
(cherry picked from commit f0bd8dbe37bd855669ad4cddff0a49bccfd9b64e)
Make sure tox is installed when setting up tempest

Partial backport of I8008837d2fae6cebeeeb051b63066279ca477e01

In order to make grenade easier to run outside of the gate make sure tox
is installed when tempest is set up. Currently one has to install tox
manually to get grenade to work.

Change-Id: Ie20de0c523cf1c31683fe69fa88f73705bed06b9
Add conntrack-tools to nova dependencies

'Error deleting conntrack entries' appears in all
n-net. Adding conntrack-tools/conntrack as nova dependency,
in order to eliminate this issue.

This is needed to fix this issue in the grenade case.

Change-Id: Ief9deeb3349a07e22fb365e58f3368c847f845ef
(cherry picked from commit 40f4438f9baa945e451f8a9fc682efe3fdf9b8f7)
Merge "Make sure tox is installed when setting up tempest" into stable/icehouse
Merge branch 'stable/icehouse' of https://github.com/openstack-dev/devstack into stable/icehouse