(#7243) Add dns_alt_names with hostname to autosign test

Lack of hostname as a dns_alt_name was producing master certs which
could not be looked up by bare hostname (as used by Beaker) in the
Jenkins environment.
Merge branch 'feature/7243/fix-autosign-command-acceptance-subjectaltnames'

* feature/7243/fix-autosign-command-acceptance-subjectaltnames:
  (#7243) Add dns_alt_names with hostname to autosign test