Set rollback status early in update if triggered

Before when rollback was triggered during stack update, the stack continued to
have status UPDATE_IN_PROGRESS, and only at the very end flipped to
ROLLBACK_COMPLETE.
This patch sets the stack state to ROLLBACK as soon as
rollback is started to notify the user properly on the action being
performed.

Change-Id: Idbd78a3a2a8d0c32fb26c7d0c38c87857d1565d8
Closes-Bug: #1316558
Heat and Openstack incomplete documentation

Improve documentation running a heat template with devstack

Change-Id: Ifb6abd30a882d4c5197090c87498781702488b9c
Closes-Bug: #1326089
Use ResourceDefinition to generate UpdatePolicy

Change-Id: I08cedd0fb9c7b804a4bf9dd5233f7b9060337a71
Get deletion policy from ResourceDefinition

Change-Id: I5e402e3ed02b9e09d3f78ef3c910c4c3d2f90fc0
Get the resource type from ResourceDefinition

Change-Id: Ie34a39a9d6d11bdbd2601e2c4be01b5411c2ac5a
Remove usages of threads in DummyThreadGroup

The patch removes creation of threads in the DummyThreadGroup class
during tests, returning a fake thread object instead. It removes some
race condition triggering tracebacks during tests.

Closes-Bug: #1330292
Change-Id: I3214816a4173670d22385dbe67cc016d74c2ce18
Merge "Heat and Openstack incomplete documentation"
Merge "Use ResourceDefinition to generate UpdatePolicy"
Merge "Get deletion policy from ResourceDefinition"
Merge "Get the resource type from ResourceDefinition"
Merge "Remove usages of threads in DummyThreadGroup"
Merge "Set rollback status early in update if triggered"