pom.xml: update killbill-oss-parent to 0.7.11

We cannot yet upgrade to 0.7.12 because of a circular
dependency.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
automaton: skeleton: disable broken/flaky tests

See https://github.com/killbill/killbill-commons/issues/4 and
https://github.com/killbill/killbill-commons/issues/5.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>