py3.7 unit test failures

[Corey Bryant]

There are async failures when running py3.7 tests.

  File "/usr/lib/python3/dist-packages/murano/tests/unit/test_heat_stack.py", line 201
    hs.push(async=True)
                ^
SyntaxError: invalid syntax

  File "/usr/lib/python3/dist-packages/murano/engine/system/heat_stack.py", line 263
    def push(self, async=False):

async is now a keyword. A possible fix is changing all uses to async_.

https://docs.python.org/3/whatsnew/3.7.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/591142

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/591142
Committed: https://git.openstack.org/cgit/openstack/murano/commit/?id=9fe87010f508b6f5bb8b862f81d92aed30280de0
Submitter: Zuul
Branch: master

commit 9fe87010f508b6f5bb8b862f81d92aed30280de0
Author: zhurong <email address hidden>
Date: Sat Aug 11 15:53:06 2018 +0800

    Fix py37 tests failed due to async

    Change-Id: If09cc4b27da22924e9ad5a5b930ccb0abcc84a34
    Closes-Bug: #1786523

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/murano 7.0.0.0rc1 release candidate.