Comment 6 for bug 1673735

Reviewed: https://review.opencontrail.org/30313
Committed: http://github.org/Juniper/contrail-vrouter/commit/c719e068f66035fd122ebd1b13d9d9f11cc0dd7c
Submitter: Zuul (<email address hidden>)
Branch: R3.2

commit c719e068f66035fd122ebd1b13d9d9f11cc0dd7c
Author: Divakar D <email address hidden>
Date: Fri Apr 7 16:50:26 2017 +0530

Update the mirror metadata len correctly

While making the Sandesh interface request structure from the VIF,
mirror metadata len is not getting initizlised to zero if mirror meta
data does not exist. This is leading to previous metadata len being used
for the current metadata and display of old metadata.

As a fix, metadata length is always initialised to zero before updating
it.

Change-Id: I8ddbdf669abeec47be9f7be021f59c39cf3f0d2d
closes-bug: #1673735
(cherry picked from commit fb65fa77d796342d68d63fdc5016eb8f03c49ad1)