With added support for multiple certificates for hosts, services, and even
users, IPA testing framework will need a more flexible way to generate
temporary testing certificates for these entities. This patch modifies the
currently used `testcert` module to support these requirements.
Related to work on http://www.freeipa.org/page/V4/User_Certificates
Reviewed-By: Milan Kubík <mkubik@redhat.com>