Comment 12 for bug 1571598

Reviewed: https://review.opencontrail.org/19448
Committed: http://github.org/Juniper/contrail-controller/commit/bf49b3c902b24072d8674d9a7fd0147b96638e87
Submitter: Zuul
Branch: R2.20

commit bf49b3c902b24072d8674d9a7fd0147b96638e87
Author: Manish Singh <email address hidden>
Date: Wed Mar 30 07:18:50 2016 +0530

Route present wih no paths.

Problem:
When only stale paths in headless mode were present and CN goes down, then walk
was issued to squash all of them. However after squashing it didnt check if
route has no paths and delete the same. So route was present with no paths.

Solution:
Re-org the squashing code in walk to go via proper removal of path and
check for zero path to delete route.

Closes-bug: #1562961

Conflicts:
 src/vnsw/agent/test/test_l2route.cc

Conflicts:
 src/vnsw/agent/test/test_l2route.cc

Conflicts:
 src/vnsw/agent/test/test_l2route.cc

Double path delete request in succession.

Problem:
In stale path cleanup, if no stale path was found function used to clean last
path seen. This resulted in not related path getting deleted. In case of OVS
delete the path to be deleted was already gone because of bug and table deleted,
resulting in ceash.

Solution:
Delete if relevant path is found.
Closes-bug: #1571598

Change-Id: I25bd7cec4c0774d0a041286c15af99bc5a2d1ada