Expose logging from docker-api

This commit exposes the logging from docker-api into the normal
beaker logging.
Make the mkdir always succeed

In some docker images the /var/run/sshd directory already exists, so mkdir will
exit non-zero and fail.  Change to mkdir -p instead.
Add RHEL variant platforms to docker hypervisor

When doing PE testing the platform name is used to determine which
PE tarball is required.  For RedHat Enterprise Linux derivatives
the platform identifier is /^el-/