packaging: Export ENGINE_DEFAULTS and ENGINE_VARS

The start scripts for the engine and for the tools don't export the
ENGINE_DEFAULTS and ENGINE_VARS environment variables. This means that
the LocalConfig class won't use its value to locate the configuration.

Change-Id: I6a41287040260eb43272c0b15af0b93eba585675
Signed-off-by: Juan Hernandez <juan.hernandez@redhat.com>