Clear Stats doesn't work - old value return

I’m trying to clear stats using traffic_line -c/-C and it doesn’t appear to work. After a couple of seconds the old values return.

CLI sample output:
traffic_line -r proxy.process.http.total_client_connections_ipv4
208
traffic_line -c
traffic_line -r proxy.process.http.total_client_connections_ipv4
0
traffic_line -r proxy.process.http.total_client_connections_ipv4
210

I think this is due to not updating the sum/count in the net-threads.
When traffic_line -c/-C is called - it clear the records table but not the net-threads sum/count variables.
In the next time the RecRawStatSyncCount func will be called it will override the "zero" value in the records table.

For example - http_total_client_connections_ipv4_stat

1. This stat is used in proxy/http/HttpClientSession.cc
2. The macro HTTP_INCREMENT_DYN_STAT using the RecIncrRawStat func to increament the stat value.
3. The RecIncrRawStat increament the sum counter on the specific net thread.
4. RecRawStatSyncCount is called in a loop and summarize all the stats in the net thread to one global value.
5. RecRegisterRawStatSyncCb is called to update the global value in the records table.

I'm attaching a patch to fix it.

1. add -z/-Z otipns to traffic_line - to reset specific stat.
2. I added a version variable to the record of the stat - so that if we want to reset a record - we will increase this record.
3. On the next sync to global call (RecExecRawStatSyncCbs in RecProcess.cc) it will clear the sum/counter in the net-tread variables.

There is another issue about the RecDecrRawStat function - I'll open on it another Jira.

Regards,
Yakov Kopel.