This patch is a part of Legacy APIs deprecation.
A Mistral workflow is created when NS is created, however, Tacker
doesn't have actual action scripts. Therefore, even though a Mistral
workflow is created, it never runs successfully due to the absence of
specified scripts.
This patch removes the dependency on Mistral for the legacy NS
create/delete APIs and also remove Mistral from Tacker entirely, as
there's no longer any place to use Mistral.
Implements: blueprint deprecate-legacy-apis
Change-Id: Iee5d109e4fdb9546730164aea94985b1c535bbc6
b1bba29dfc