Parse deployments if found in cfn metadata

Will result in multiple cache files to be merged per
OS::Heat::StructuredDeployment. This is needed as the new features for
software configuration break things up a bit differently in Metadata.

Change-Id: Iec0fd947bac674f6b6f36e8c0789d10580c325fd
Closes-Bug: #1295787
Merge "Parse deployments if found in cfn metadata"