Move to consolidate heat.conf

Upstream changes [1,2] modify heat to use a single config ([3] is a
change to the upstream puppet modules to produce a single .conf).
This modifies the init file to use that.

[1] https://review.openstack.org/#/c/39980/
[2] https://review.openstack.org/#/c/43697/
[3] https://review.openstack.org/#/c/43406/
Merge pull request #3 from ianw/config-in-one

Config in one