ppc64le: Create legacy logs directory
ppc64le: Create legacy logs directory

build.log is now created in {{ workspace }}/logs which we were not
creating. This patch ensures the directory exists so the container
build job won't fail.

Change-Id: Ifb312175d2a69074a55688fec62c4ce2fbdd13d5

rdo-infra/ci-config,redhat-openstack/rdo-infra,redhat-openstack/rdo-infra,redhat-openstack/rdo-infra,rdo-infra/ci-config,redhat-openstack/rdo-infra,rdo-infra/ci-config,rdo-infra/ci-config