LBaaS: handle NotFound exceptions in update_status callback

LBaaS agent may send update_status requests to server on objects
which were already deleted from db: this is due to creating and
deleting objects with a high rate (like tempest API tests do).
As a result errors and stacktraces appear in server and agent logs.
The proposed solution is to catch NotFound exceptions and print a warning.

Change-Id: I4446b678893d0bda578ad7ccdf3f109cb1c91b4d
Closes-Bug: #1260682
Fix race condition in delete_port method. Fix update_port method

Port can be gone between
  l3plugin.prevent_l3_port_deletion(context, id)
and port query. Need to handle it properly.
ALso need to handle non-existing port in update_port properly.

Closes-Bug: #1266537

Change-Id: Ic203f21db277f83c604a8757a8c421b3fb9ae709
Remove garbage in vim header

Introduced by commit 9d01010e8826eafc48044fc4018944a34bc96ba4

Change-Id: I97c7789fa13e61d16466cddac49fc41d1f917e80
Reduce severity of log messages in validation methods

I noticed this while reviewing Ic2c87174.  When I read through log
files, I don't want to see errors like this that come from validating
bad user input.  Info severity is more appropriate.

Change-Id: Ib8a4dd08570923c6cade6447b52bb73d20558258
Closes-Bug: #1272565
Change metadata-agent to spawn multiple workers

There is currently only one metadata-agent per network node,
which could be handling connections from hundreds or thousands
of metadata-namespace-proxy processes.

This change addes a new "metadata_workers = XX" to the ini file
to support creating more workers to help improve performance.

Change-Id: Ib9ebcfc543a83982dd93db79c7dc631283fd3bfa
Partial-bug: #1274536
Change metadata-agent to have a configurable backlog

The metadata agent currently runs with a default socket backlog
of 128.  This isn't enough on a busy network node, even when
spawning multiple worker processes.

This change addes a new "metadata_backlog = XX" to the ini file
to support a configurable value to help improve performance.

Change-Id: Ibea398f3b65a56deb1418f39810d87d8360ea9f3
Closes-bug: #1274536
Avoid re-wiring ports unnecessarily

In the majority of cases a port_update notification pertains
a change in the properties affecting port filter, and does
not affect port wiring, ie: the local vlan tag.

This patch simply avoids doing port wiring/unwiring if the
local vlan tag did not change.
The extra overhead for the ovs-db get operation is offset
by the fact that get commands are generally faster than
set commands, and by avoiding executing the ovs-ofctl operation.

Partial-Bug: #1253993
Partially implements blueprint: neutron-tempest-parallel

Change-Id: Ia0bd2dc4e5a2634a4c863ff32ccc5cabe8e21337
Merge "Avoid re-wiring ports unnecessarily"
Merge "Change metadata-agent to spawn multiple workers"
Merge "Change metadata-agent to have a configurable backlog"
Merge "Reduce severity of log messages in validation methods"
Merge "Fix race condition in delete_port method. Fix update_port method"
Merge "Remove garbage in vim header"
Merge "LBaaS: handle NotFound exceptions in update_status callback"