disable pw_hash test on sles, as it only supports md5
disable pw_hash test on sles, as it only supports md5

HelenCampbell/puppetlabs-stdlib,puppetlabs/puppetlabs-stdlib,yadavnikhil/puppetlabs-stdlib,DavidS/puppetlabs-stdlib,jbondpdx/puppetlabs-stdlib,fuel-infra/puppetlabs-stdlib