Comment 8 for bug 1651084

Reviewed: https://review.openstack.org/417794
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=4db4f1e904fe12d794df0e3542ba4ba3a39e9f41
Submitter: Jenkins
Branch: stable/newton

commit 4db4f1e904fe12d794df0e3542ba4ba3a39e9f41
Author: huangtianhua <email address hidden>
Date: Tue Dec 20 20:29:59 2016 +0800

    To reset metadata for resources when mark unhealthy

    Some resources do not work if their metadata is in
    a wrong state, .e.g the metadata 'scaling_in_progress'
    of scaling group/policy might be always True if engine
    restarts while scaling.
    This patch adds an interface 'handle_metadata_reset' for
    resource, then the plugins can override it if needed.
    We reset the metadata while marking resource healthy.

    Closes-Bug: #1651084
    (cherry picked from commit 5b04acb4e25efbea58de998278e390fb64d7c575)

    Conflicts:
     heat/tests/engine/service/test_stack_resources.py
    Change-Id: Ibd6c18acf6f3f24cf9bf16a524127850968062bc