Remove testscenarios load_tests

A load_tests call sneaked in test_provider_template, but it's become
useless since we switch to a base heat test class that provides what's
needed.

Change-Id: Ie5665cbbafb46a7ed63ada37a3f4aa5c74cdb8b6
Allow NotFound to be created without args

It appears that the serialization used to wrap RPC exceptions
requires that the class be instantiated without any arguments.

Since the NotFound exception required a msg_fmt it could not be
deserialized in heat-api, which lead to no mapping in the FaultWrapper
so a 500 was raised instead of a 404.

This change adds a default value for msg_fmt for the NotFound exception.

The classes Error and ResourceFailure likely have this issue too, but it
is not as serious since they will raise a 500 error anyway.

Config/deployment API tests now check that NotFound can be deserialized by
calling to_remote_error, and checks that FaultWrapper converts that to
HTTPNotFound.

Change-Id: Ieb8de26465cb26aa015f15c134f80a06ebcae95c
Closes-Bug: #1301657
Related-Bug: #1304743
Add documentation for creating a resource plug-in

Change-Id: I229316c6f4c634c18fc33b0f5ffd3ce5d194b383
More specific exceptions when validating params

In addition to the example cited in the bug, this updates a few other
exception messages to indicate the name of the parameter that is failing
validation.

Change-Id: I1b7729305988444dc15abd6e5d958f443efc091d
Closes-Bug: #1294295
Add missing test coverage for XMLResponseSerializer

Currently we have no direct coverage of this, so add some tests
prior to refactoring in a subsequent patch.

Change-Id: I20242e60b84f9265cdc7afef2deabee8235e287c
Related-Bug: #1291079
Refactor to separate serializers from wsgi controller

Remove the serializers from heat.common.wsgi, so we break the
circular import which happens if you want to import
heat.api.aws.exceptions to do a determination based on exception
type, which is required to avoid the faultwrap exception disguise
which is not applicable to the CFN API.

Partial-Bug: #1291079

Change-Id: I7498d78f8ec6098b28fb183eaaa04aa81fced3eb
Don't disguise CFN API exceptions

The exception disguise wrapper is for the native API which uses
the faultwrap filter to process the response. For HeatAPIException
subclasses (which are only raised by the CFN/CW API's) we need to
raise the unwrapped exception or the client sees a 500 response.

Change-Id: Iebfbc76d5cb26aa9ee61c5192d7fecc596aa83b9
Closes-Bug: #1291079
Merge "Remove testscenarios load_tests"
Merge "Allow NotFound to be created without args"
Merge "Add documentation for creating a resource plug-in"
Merge "More specific exceptions when validating params"