Do not advertise L2 addresses if VN is configured to be L3 only

[Nischal Sheth]

Agent should not advertise L2 addresses to CN if VN is configured with
forwarding mode L3 only. Both unicast and broadcast routes should not
be advertised.

Doing this avoids exercising unnecessary code in CN and reduces number
of routes in the system. It is expected that Kubernetes will create L3
only networks by default.

Agent should continue to process any L2 routes received from CN. This
is required for correctness when forwarding mode transitions from L3 to
L2+L3.

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/21500
Submitter: Manish Singh (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/21500
Committed: http://github.org/Juniper/contrail-controller/commit/64a26612ee7f28844854f4252f701800d4417165
Submitter: Zuul
Branch: master

commit 64a26612ee7f28844854f4252f701800d4417165
Author: Manish <email address hidden>
Date: Tue Jun 28 16:23:01 2016 +0530

In L3 mode, no L2 routes are advertised.

- mac of VM is not added with local vm port path.
- mac still gets added with mac-vm binding peer, as vrouter needs it for source
check. However it points to discard NH. Export gets blocked because there is no
local vm peer path.
- broadcast subscription for evpn does not happen, fabric mcast will be send.
- Routes sent from CN in evpn are accepted and no fwding mode is applied.
- OVS is not blocked.

Along with these changes, some more optimization are present.
- Removal of multicast NH, as its not used.
- Moved L2 interface NH under common interface config. It gets added if any of
the modes i.e. ipv4/ipv6/l2 is enabled and gets removed when all are disabled.
This is done as fabric multicast uses these NH and that is sent irrespective of
mode.

Change-Id: Ic48f5c48aa4fd89c7431db2caebea3bd7cf05fd0
Closes-bug: #1564724

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/21803
Submitter: Manish Singh (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/21803
Committed: http://github.org/Juniper/contrail-controller/commit/e7151580d816ed04037872fa7d3b911fc4558894
Submitter: Zuul
Branch: R3.0

commit e7151580d816ed04037872fa7d3b911fc4558894
Author: Manish <email address hidden>
Date: Tue Jun 28 16:23:01 2016 +0530

In L3 mode, no L2 routes are advertised.

- mac of VM is not added with local vm port path.
- mac still gets added with mac-vm binding peer, as vrouter needs it for source
check. However it points to discard NH. Export gets blocked because there is no
local vm peer path.
- broadcast subscription for evpn does not happen, fabric mcast will be send.
- Routes sent from CN in evpn are accepted and no fwding mode is applied.
- OVS is not blocked.

Along with these changes, some more optimization are present.
- Removal of multicast NH, as its not used.
- Moved L2 interface NH under common interface config. It gets added if any of
the modes i.e. ipv4/ipv6/l2 is enabled and gets removed when all are disabled.
This is done as fabric multicast uses these NH and that is sent irrespective of
mode.

Closes-bug: #1564724
(cherry picked from commit 64a26612ee7f28844854f4252f701800d4417165)

Conflicts:
 src/vnsw/agent/oper/test/test_intf.cc
 src/vnsw/agent/oper/vm_interface.cc
 src/vnsw/agent/oper/vm_interface.h
 src/vnsw/agent/test/test_agent_db_entry.cc
Change-Id: Ic48f5c48aa4fd89c7431db2caebea3bd7cf05fd0