Use apt-get to install python-minimal
apt does not refresh the package mirrors for the jobs
run within the Jenkins, and fails to install python-minimal.
With apt issue is reproducable:
https://logs.opendaylight.org/releng/vex-yul-odl-jenkins-1/builder-packer-merge-ubuntu-16.04-docker/74
With apt-get as a workaround resolves the packages with the mirrors sussessfully:
https://logs.opendaylight.org/releng/vex-yul-odl-jenkins-1/builder-packer-merge-ubuntu-16.04-docker/73
Issue: RELENG-2548
Change-Id: I3436fa250bff5b90e2b4c390a97c0b989b52d7af
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>