Fixed NO_UPDATE_REPOS variable usage

Change-Id: I50a2fd73f30321e97c99947b62fb1729870a2c14
Add DVR support to DevStack

This patch introduces a new Neutron  config option: Q_DVR_MODE.

The possible values are:

- legacy  : No DVR functionality
- dvr_snat: Controller/single node DVR
- dvr     : Compute node in multi-node DVR

When DVR is enabled the following configuration changes will be
in place:

- neutron.conf
  - router_distributed=True

- l3_agent.ini
  - agent_mode=$Q_DVR_MODE

- ovs_neutron_plugin.ini:
  - enable_distributed_routing=True
  - l2_population=True
  - tunnel_types=vxlan

Supports-blueprint: neutron-ovs-dvr

Change-Id: I669e054a8489fe7ac7f5c00df6535349d477e8c4
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
add is_keystone_enabled

This is missing, and makes logic much harder for the grenade use
case.

Change-Id: Ib6670096d190e69273256b87e6a67e2b46945a0d
Merge "Fixed NO_UPDATE_REPOS variable usage"
Merge "Add DVR support to DevStack"
Merge commit 'refs/changes/83/86083/2' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch