Clarify a comment which says we require KeyName - which is incorrect

The Nova create API requires a name, image, and flavor.  The key_name
is not mandatory.  Possibly in AWS InstanceType (flavor) is not
mandatory but it is with Nova.

blueprint native-nova-instance

Change-Id: I6f5a77d7999ea4d8e91402ae215179b982a947f6
add error flow tests for volume detach

engine.resources.volume.VolumeAttachment lacks tests for some
exception flows

Fixes bug #1183239

Change-Id: I3d84fadb1ff60c622fbfbd634e003aaab382b405
Allow stacks to be created without a timeout

This should be the default for nested stacks, rather than the default
timeout of 60 minutes for stacks created through the API.

Change-Id: Iacee6eaf8f345e506b417e776f696db6b11bbf20
Implement timeouts for nested stacks

This also means that if no default is specified, nested stacks will not
time out (previously they used the default timeout of 60 minutes). Of
course, like other resources, creation of the nested stack will stop if and
when the parent stack times out.

Change-Id: Ibd55c32d63e971f79319ed40321fa4be52b65419
Create stacks with a co-routine

This will allow nested stacks to be created in parallel with other stack
resources in the future.

Change-Id: If1817bddcea50fdd7b640dee5b5d12257aada651
Create nested stacks in parallel

Use check_create_complete() to advance the nested stack creation, so that
it can occur in parallel with other resources in the parent stack.

Implements blueprint concurrent-resource-scheduling

Change-Id: I841b4c93b257409eecd0d2a43b35d9bee114ab87
Merge "Clarify a comment which says we require KeyName - which is incorrect"
Merge "add error flow tests for volume detach"