Enabled request_id in RequestContext

As a means to enable logging on request id's, request_id in the RequestContext
can be set.

blueprint log-request-id

Change-Id: I13cd494d5af3255c03ec30e1040ef01c856c960d
Handle NetworkNotFoundClient and PortNotFoundClient

neutronclient has changed is behavior (recently?) in that it now
raises PortNotFoundClient for missing ports and NetworkNotFoundClient
for missing nets. These exceptions extend NeutronClientException but
do not set the status_code to 404 so the existing resource 404
checking has stopped working.

This change handles both 404 exceptions and the new exceptions
so that it continues to work with different neutron releases.

Change-Id: Id06e04d4b98e62b8062b119e959634fd61c8beb5
Closes-Bug: #1234924
Don't obtain resources through stack.resources

A particular logical resource name can be looked up by subscripting the
stack object directly.

Change-Id: I621280318cfb104ab9bfe1ae7c31fe2b5e55cfc6
Unit tests: don't use status strings from class

We should always obtain the status strings from the object we're actually
using them with. In this test, the parser.Stack class is actually stubbed
out, which can cause problems for accessing its attributes.

Change-Id: I8e060c6c937542dd11e96f243af26ee4dfa348dc
It is necessary to update pool_id for Neutron LB

Closes-Bug: 1235903
Signed-off-by: Stephen Gran <stephen.gran@guardian.co.uk>
Change-Id: Ie48312efd7f04c425436b8dae9c8bccf21dc768e
allow "members" property to be absent

Closes-Bug: #1235904
Change-Id: If18f6d386d07ee65ce54f8372ad646864b486303
Signed-off-by: Stephen Gran <stephen.gran@guardian.co.uk>
Merge "It is necessary to update pool_id for Neutron LB"
Merge "Don't obtain resources through stack.resources"
Merge "Unit tests: don't use status strings from class"
Merge "Handle NetworkNotFoundClient and PortNotFoundClient"
Merge "Enabled request_id in RequestContext"