Cleanup: Remove obsolete Fuel@OPNFV patches

Cleanup: Remove obsolete Fuel@OPNFV patches

Since we are now building inside docker containers, it is no longer
necessary to use `python-debian` from pip repo instead of Ubuntu.

Also, since Fuel@OPNFV improved our mirror selection in [1], we
can drop our custom blacklist entries for Ubuntu SE mirrors, as
well as repeating the repo mirror build in case of failure.

[1] https://gerrit.opnfv.org/gerrit/#/c/22195

Change-Id: I62890b6ae7977cd8a39c06ce17c8964e6cb1dddb
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>