Add support for VXLAN to the Open vSwitch plugin.

This commit adds support for utilizing the VXLAN tunneling protocol in versions
of Open vSwitch >= 1.10. This is configurable and will default to GRE if not
configured. As part of this commit, it is possible to configure the UDP port
VXLAN will utilize as well. VXLAN and GRE cannot be configured at the same
time with this patch. 2 new configuration file options are added to the AGENT
section of the config to support this: 'tunnel_type' and 'vxlan_udp_port'.
In addition, the agent no longer makes use of enable_tunneling, as this can
be determined if tunnel_type is set.

Note: The VXLAN functionality utilized here is what is implemented in Open
vSwitch itself, and is different than the VXLAN functionality in the
upstream Linux kernel. The code validates both the userspace and kernel
pieces of OVS to verify if VXLAN functionality can be supported on the
running system

Implements blueprint ovs-vxlan-lisp-tunnel

Change-Id: I45d49d5d6463e574922c7f50d6499c6bdb6c862c
Remove explicit distribute depend.

Causes issues with the recent re-merge with setuptools. Advice from
upstream is to stop doing explicit depends.

Change-Id: Idb465068d25433582b8579a3ea96293f23368708
Ensure to remove auto delete ports from OFC in NEC plugin

When deleting a network, dhcp ports are removed automatically
in db_plugin. This causes a failure network deletion since the
corresponding port exists on OFC and the network on OFC cannot
be deleted unless a subnet on the network is deleted explicitly.
This commit gets auto-delete ports and delete the corresponding
ports on the controller before deleting the network.

Fixes bug #1190163

Change-Id: Ifffaa1a28b5fac0b0a98036a926550255cc25c9d
Imported Translations from Transifex

Change-Id: Ia5f18e90d6df17c1b4d758fa949259d8af489e5d
Merge "Ensure to remove auto delete ports from OFC in NEC plugin"
Merge "Add support for VXLAN to the Open vSwitch plugin."
Merge "Imported Translations from Transifex"
Merge "Remove explicit distribute depend."
Make reference lbaas implementation as a pluggable driver

implements blueprint multi-vendor-support-for-lbaas-step1

This patch implements the following changes:
 * merge lbaas_plugin.py and plugin.py into 'plugin.py'
   After that the default 'reference' implementation is available again.
 * move all code related to reference implementation from plugin.py to
   drivers/haproxy/plugin_driver.py
 * Inherit HaproxyOnHostPluginDriver from abstract driver and implement
   its interface.
 * modify tests accordingly

Change-Id: Ib4bfe286826acdedeadbeeff4713448c073378d2