packaging: engine-service: major cleanup

Last patch in series of engine-service, after all core issues merged
into existing implementation, this introduce python only rework and
cleanups.

 1. Removal global variable.
 2. Previous patch already use python subprocess instead of direct exec.
 3. Use python logging instead of direct syslog calls.
 4. Add debug log.
 5. Add debug parameter.
 6. Add gettext support.
 7. Modular functional.
 8. Remove one time used variables.
 9. Remove replication of configuration variable into local variables.
10. Remove dead code.
11. pyflakes free
12. pep8 complaint.

Change-Id: Iea45e8131190f41171e937699ec2e261939c4bd9
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>