Comment 5 for bug 1381821

Reviewed: https://review.opencontrail.org/5843
Committed: http://github.org/Juniper/contrail-controller/commit/c4e33530753b9c3a221abb958f81e4164a585f5e
Submitter: Zuul
Branch: master

commit c4e33530753b9c3a221abb958f81e4164a585f5e
Author: Naveen N <email address hidden>
Date: Sat Dec 20 02:02:31 2014 -0800

* Upon local mpls ecmp label deallocation, control-node would withdraw
this mpls label in its path, if the label gets reused even before
control-node retracts the label, due to quick activate and deactivate
of the interface(oper state change), then mpls label in BGP path would
point to internface NH, instead of composite NH as expected.
Re-evaluation of BGP peer happens because it was one of the ecmp interface
that got deactivated and added again.
Add a check to verify that local ecmp mpls label is not deleted.
Unit test:
Created ecmp with 2 instances, add the same route with aggregarte mpls
label via bgp peer, deleted both interface so that route update is
sent to BGP to withdraw this path, before BGP peer could withdraw
same instance would be activated with aggregarate mpls label and
route change would be triggered, verify that no crash is seen,
and update of path happens fine
Closes-bug:#1381821

Change-Id: I27a0f8ca0f011cc4bab3de79787356d32563c4d6