This patch implements the versioned notifications for flavor
create and destroy.
Implement blueprint: flavor-notifications
Change-Id: Icc2169b87ffba4e7e2079076a82029156c584c6a
Add instance's locked field and instance's
display_description field in InstancePayload.
Implements: bp additional-notification-fields-for-searchlight
Change-Id: Iceae25ca8a0d7f2e5f22cab1364215bda2fae93c
Along with the transformation changes, I modified notify_about_instance_action
method so it can handle errors now. (It wraps the exception object into an
ExceptionPayload.)
Implements: bp versioned-notification-transformation-ocata
Change-Id: I171990290c8de529c9521a5ee556f97b18b741b0