Fix intermittent failure in verify-rpm

Running the verify-rpm job over and over, it fails something like 80% of the time. The error is always that the default ports don't open after installing and starting ODL. The same logic works for other tests.

Working against master: https://logs.opendaylight.org/releng/vex-yul-odl-jenkins-1/packaging-verify-rpm-master/51/console.log.gz

Failing against master in the next run: https://logs.opendaylight.org/releng/vex-yul-odl-jenkins-1/packaging-verify-rpm-master/52/console.log.gz