Comment 12 for bug 1757966

Reviewed: https://review.openstack.org/564462
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=b77769cf447ee85892da676b77189320f1ad838d
Submitter: Zuul
Branch: master

commit b77769cf447ee85892da676b77189320f1ad838d
Author: Renat Akhmerov <email address hidden>
Date: Thu Apr 26 18:10:18 2018 +0700

    Get rid of a extra copy of workflow environment

    * Previously, we had two copies of the workflow environment
      passed by a user: one was in the 'params' fields under ke 'env'
      key and another one was copied into the 'context' field under
      the '__env' key so that we can evaluate expressions involving
      the env() function (YAQL or Jinja).
      This patch removes the copy from the 'context' field in favor
      of using an ad-hoc ContextView structure where we now also
      weave in the environment dictionary under the same key '__env'.

    Related-Bug: #1757966
    Change-Id: I1204b082794b376787d126136a79dd204ec3af07