Since ubuntu 16.04 or so the krb5-admin-server package is broken in the
postinst scripts. What happens is they try to set a debconf value if the
defaults file for this service sets RUN_KADMIND to false. Unfortunately
the key/question debconf is setting has no associated templates entry so
package install fails.
We work around this by not setting this value in the defaults file on
newer ubuntu and instead rely on our init system to manage that state.
Change-Id: I0ffe2a2acbe76acb0069df18253367ed2528241f
672583bd10