engine.pp: removed undefined Heat_engine_config

Change-Id: Ie9e6389aa65aebfa8f6561cea24dfae84736665b
Consolidate config into single file

Upstream commit [1] modified heat to use a single config file.  This
modifies the puppet config of each component to use different sections
of the same file.

Fixes bug 1214824

[1] https://review.openstack.org/#/c/39980/

Change-Id: I7d8865a809da71696b944ab0654a1f728cd827df