Comment 14 for bug 1755768

Reviewed: https://review.opencontrail.org/40807
Committed: http://github.com/Juniper/contrail-controller/commit/892dfeca432c50e64752ce6981ff34eff5d0f735
Submitter: Zuul (<email address hidden>)
Branch: R4.1

commit 892dfeca432c50e64752ce6981ff34eff5d0f735
Author: Ananth Suryanarayana <email address hidden>
Date: Mon Mar 19 05:19:28 2018 -0700

Provide local-as configure-ability for each bgp session

Some bgpaas deployments need different peer AS number for each bgpaas session
(on the control-node) side. Hence, provide a local-as support on a per bgp peer
basis

o local_as_ is already of BgpPeer. It was always populated with either the
global asn or (per control-node) local asn. With this change, if local-as
is configured on a per peering session, then that local-as takes precendence.
o Add unit tests to test this per per specific local as
o Parameterize bgp_bgpaas_test to test with per peer local-as configured or
otherwise
o Tweak RibOut policy to create sepearte ribouts if local-as field differs
o During as-path prepend, either global local-as or per peer local-as is
prepended for ebgp sessions.
o AS Override shall now override with per peer local-as if configured,
global local-as otherwise

Change-Id: I2d1e30820195c2eacf392317c235ac40ad7ce027
Partial-Bug: 1755768