Analyze re-raised exceptions in Cisco Plugin

Checked all cases of re-raised exceptions. In several cases, the exception
was redundant (re-raising the same exception), so the try block and
exception handling was removed.

In one case, exceptions raised from two sources were re-raised with a
a different exception. Instead of doing this, the original exceptions
were changed and the try block and re-raised exception were removed.

In cases where there were database exceptions that were re-raised as
Neutron exceptions, the traceback was left as-is, since it was more
informative to know the higher level source of the issue.

The same was true for the exception mentioned in the bug, where the
original failure was in the ncclient library parsing the configuration
and it would be more descriptive to know that there was a connection
failure or a config failure, that to know the library method.

bug 1213159

Change-Id: Ie334d2548bf651c61e878bf797adaf8c5880eb86
Add extra_dhcp_opt extension to BigSwitch/Floodlight plugin

Adds support for the DHCP options extenion to the
BigSwitch/Floodlight plugin.

Fixes: bug #1206655
Change-Id: Ida30ca44ecbb9d1208303e47519427a4111f6025
Merge "Analyze re-raised exceptions in Cisco Plugin"
Merge "Add extra_dhcp_opt extension to BigSwitch/Floodlight plugin"
Refactor BigSwitch error handling to use db rollbacks

This patch adjusts most of the logic handling the
calls to the controller in the BigSwitch/floodlight
plugin to make use of the db rollbacks from
sqlalchemy for free on exceptions. This eliminates
several complex try-except blocks and makes
maintaining db<->controller consistency easier.

Fixes: bug #1215823
Change-Id: Ia636c40e744b3b1c543e891791bf492df4f675d2
Multi-segment and trunk support for the Cisco N1Kv Plugin

This patch adds vlan and vxlan trunk support in the
Cisco N1Kv plugin. It also adds support for multi-segment
networks for bridging vlan networks with vxlan networks.

Change-Id: Ibecbbfbce1eb4d18ef6a1bc5250622b9ae87d39c
Implements: blueprint multi-segment-and-trunk-support-cisco-nexus1000v
Fix DHCP agent to work without extra_dhcp_opt extension

With the introduction of extra_dhcp_opt extension, DHCP agent
stopped serving mac adresses when used in conjunction with a
plugin that doesn't support this extension. This fixes the agent
by not assuming that port dict contains extra_dhcp_opt key.

Closes Bug: #1219893

Change-Id: I5bb52f3092f04c5e332b43cb3a04de05edc29cf5
Add l2 population base classes

This patch initiates the blueprint l2-population
Implemented as a ml2 Mechanism driver.

OVS & LinuxBridge drivers will be added as dependencies.

Change-Id: Ia2345aa262ec791c9f38b6e41e1e4b46f69cadac
OVS agent implementation of l2-population

This patchset implements l2-population RPC callbacks in OVS agents,
it enables plugin to populate forwarding table following portbindings
events.

For now, it doesn't include ARP responder implementation which is
deferred to a future patchset (As this feature isn't yet supported by
OVS, it will require the use of an external responder such as ebtables)

It anyway brings some improvements in tunnelling management, as agent
will tear-down unecessary tunnels, and flood packets on a per-network
basis rather than to all other agents.

These changes should anyway have a limited risk, as tunnel management
won't be affected as long as l2-population is not set. This option must
be used in conjonction with ml2 plugin using l2population mechanism driver.

Implements: blueprint l2-population

Change-Id: I5185eefedb0ff392bc8b99d16f810813e26ff58d