A new UVE message is added in collector to keep track of the sandesh
messages statistics per minute. Current counters track only the running
sum since epoch.
Code changes:
A new UVE sandesh message is added in collector_uve.sandesh
In generator.cc, functions to update the statistics counter for
each messages and get the per minute statistics for each mesasge
is added.
In collector.cc, a function that gets called every min to get all
the stats collected from each generator is provided. After that it
gets sent.
Changes made in generator.h to make the vaiables atomic.
The variables are being read/written by different threads
and to avoid any consistency problem, making it atomic
Merge pull request #233 from Juniper/arvind-sandeshstats

A new UVE message is added in collector to keep track of the sandesh