kx509 fails to create certs for principals with slashes in them. For
example:
client% kinit foo/admin
foo/admin@EXAMPLE.COM's Password:
client% kx509
Timed out waiting on KCA
The KCA reports: "Principal is not a user." However, there is a use
case set out in this post:
https://thestaticvoid.com/post/2012/10/25/protecting-puppet-with-kerberos/
that would create a kx509 cert for a host principal for authenticating
against a secure HTTP service. This commit modifies the certificate
creation code to allow principals with slashes in them.