test_engine_service remove redundant DummyThreadGroups

Remove DummyThreadGroup assignments, since they are assigning to an
EngineService attribute which no longer exists (it's a legacy from
an older heat-engine implementation)

Change-Id: I60de53e88eeb56ab36ec7f3a697fd856b1a84925
Remove unnecessary coding line

As per PEP 263, a Python file with non-ASCII characters must have a
line with "coding: <some-encoding>". This file is pure ASCII, so the
line is unnecessary.

Change-Id: I73d07bc0d80ac4dab484bf2a311818a5f6489dc0
Implement context manager for stack lock

This is to give the engine service methods a means to use the stack lock
that guarantees it will be released if there is an exception.

Change-Id: I6d0e1e7c22f4e74eeb069f980bc09a14f3740beb
Partial-Bug: #1321011
Use stack lock context manager in abandon & delete

This will ensure that the stack lock is always released when there is an
exception.

Change-Id: I6d65c57d8b92107eb84c5ed1fbfd5eca30bace01
Partial-Bug: #1321011
Remove support for nova volumes

Note this is only supported if for some reason cinder client
is not imported, which seems rather random.

Change-Id: Id57ba93ef8202ba2a513ee21aff02e4dac9ec21e
Merge "Implement context manager for stack lock"
Merge "Use stack lock context manager in abandon & delete"
Merge "Remove unnecessary coding line"
Merge "Remove support for nova volumes"
Add a ResourceDefinition class

This class provides a comparable, hashable representation of a resource's
definition in a template that is independent of the template format.

Implements: blueprint resource-template-api

Change-Id: I183114596863fbe0c0ff7cd22134b37493ed0dd9
Use ResourceDefinition for creating Resources

Initialise resources with a ResourceDefinition object rather than a JSON
snippet from a template. We no longer need to store the json_snippet (since
the resolving of intrinsic functions is reversible when necessary), so get
rid of it.

Change-Id: I23d183d986ab1d771407502ec926e736d1f48d79
Get the dependency graph directly from functions

Prior to this change, while template formats were pluggable, only the
intrinsic functions defined by HOT and CloudFormation could affect
the dependency graph. This moves knowledge of the template format out of
the Resource class and allows the ResourceDefinition to determine it in a
format-independent manner by collecting it from the intrinsic functions
defined by the template plugin.

Change-Id: I592ac2074a600a44578ce97309def1280c72e61d
Merge "test_engine_service remove redundant DummyThreadGroups"
Merge "Add a ResourceDefinition class"
Merge "Use ResourceDefinition for creating Resources"
Merge "Get the dependency graph directly from functions"